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13: Gemstone Treatments and Enhancements - Geosciences


13: Gemstone Treatments and Enhancements - Geosciences

Mines and Geosciences Bureau Region 13 (Philippines)

Caraga Region is located at northeastern part of Mindanao. [1] It includes the five provinces of Dinagat Province, Surigao del Norte, Surigao del Sur, Agusan del Norte [2] and Agusan del Sur. [3] Caraga Region is now hosting several mining projects producing various mineral commodities particularly but not limited to gold, copper, chrome, nickel, iron and limestone for concrete cement production. This makes the Department of Environment and Natural Resources, [4] Mines and Geosciences Bureau, [5] Regional Office No. 13 [6] with Office located in Surigao City plays important role in the region's economy, job generation, social and environmental enhancement and protection and ensuring government shares through royalties and taxes.

Caraga Region is one of the regions notably located in the eastern seaboard of the Philippines. With its geographic location facing the Pacific Ocean and famous Philippine Trench, the Region is prone to various weather conditions and geologic phenomenon like, but not limited to, typhoon, tsunami and other coastal surges and seismic activities. With these, DENR-MGB13 is expeditiously utilizing its human and financial resources to generate geohazard maps as necessary source of information to spatial planners and other government and non-government agencies working for public safety and disaster management.


Gemstone Radiation Treatment

Most gem buyers will accept that heat transforms brown zoisite to blue tanzanite and purple quartz (amethyst) into yellow quartz (citrine). The gem industry has used heat enhancement for many years. On the other hand, gem dealers worry that an ill-informed public would refuse to buy jewelry containing irradiated stones. Of course, gemstone radiation poses no health risks as long as the process is carefully controlled.

What is Radiation?

The term “radiation” covers a number of phenomena which fall into two groups: electromagnetic and particulate.

Electromagnetic Radiation

Radio waves, microwaves, and visible light are the most well-known forms of electromagnetic radiation. These all consist of photons, or small “clumps” of vibrating electric and magnetic fields, moving through space at light speed. The faster the vibration, the more energy (and smaller wavelength) a photon has.

Visible light vibrates at a mere 10 14 times per second and has relatively low energy. As the frequency increases and the wavelength gets smaller, we pass through the ultraviolet spectrum, first to X-rays and then to gamma rays. These can have hundreds or thousands of times as much energy as visible light.&hellip

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This technique has been used for centuries to treat Ruby gemstones. It is used to improve the clarity and colour of Rubies. The Ruby is placed in a crucible and heated to extreme temperatures of around 1800 degrees. The atmosphere around the Ruby can be altered to change the way the Ruby reacts but the basic idea is that the heat will dissolve any rutile inclusions inside the stone which will improve the clarity and improve the red colour. No other additives have been added to the process and the Ruby is as strong and durable as the unheated version.


Internal Laser Drilling (Made to Resemble Natural Flaws)

Besides using lasers to create surface reaching tunnels, newer methods of internal drilling had also been researched and applied in recent years. You are probably wondering why would people want to use internal laser drilling instead of the traditional laser tunneling?

Well, the reason behind using internal drilling involves a malicious intent to deceive consumers as this treatment is often undisclosed .

You see, internal laser drilling creates many small cleavages with seemingly non-discernible patterns. These “tunnels” serve the purpose of bridging the inclusion to the surface without the use of a direct laser tunnel.

The problem with these irregular and worm-like looking channels is that they are purposely made to resemble feathers and passed off as being “natural” flaws.

Artificial treatment that resembles natural feather inclusions.

For this type of treatment, diamonds with dark inclusions near their surfaces are usually selected for enhancement. After the worm-like channels are drilled, the diamond is subjected to a series of bleaching solutions to dissolve the unsightly inclusions.

Black coloration is significantly reduced after treatment

Both dark crystal and feather are no longer that obvious after laser drilling

Source: A New Lasering Technique For Diamond (GIA)

Important note: always ask for a GIA or AGS certificate when buying a diamond. If the jeweler refuses to show you one or tries to promote other reports of dubious origins, it immediately subjects the diamond to suspicion.

Besides grade bumping or clarity enhancements issues, I can tell you from experience that the jeweler is not only trying to rip you off but also likely be hiding other major issues from you.

Besides grade bumping or clarity enhancements issues,


Rocks N Minerals

Composition: Calcium Carbonate
Uses: In cements and mortars, production of lime, limestone is used in the steel industry glass industry, ornamental stone, chemical and optical uses and as mineral specimens.

Composition: Copper, commonly associated with iron and silver
Uses: Native Copper was the only source of copper until the turn of the century, when extraction methods were improved. The copper ores are far more abundant than Native Copper, and are therefore the main source of copper nowadays. Even though, Native Copper is a sometimes mined as a minor ore of copper. Copper ranks second for as most-used metal in the world. The special properties of conductivity, malleability, resistance, and beauty make it so popular. The main uses of copper are electrical, due to the greatness of copper&rsquos conductivity, which offers the lowest electrical resistance after silver. Copper is very ductile and can be drawn into very thin wires, which serves as its primary electrical function. It is used for electrical machinery such as motors, electromagnets, generators and communication devices.
Copper has been fashioned into ornamental objects and cooking utensils. Coins have been made of copper throughout history.
Copper is also used in pigments, insecticides, and fungicides, although it has of lately been largely replaced by synthetic chemicals.

Composition: Iron chromium oxide, sometimes with some magnesium. Forms a series with the much rarer Magnesiochromite.
Uses: Chromite is the main ore of chromium

Composition: Gold, with small amounts of silver sometimes also copper and iron
Uses: Gold has been used as a precious metal throughout the history of mankind. This is due to its resistance, beauty, rareness, and the fact that it is very easy to work with. In addition, in the olden days gold didn&rsquot have to be extracted, because a large amount was found in a pure state. Many gold ornaments from the past have been found. Most noted are from the tombs of the Pharaoh in Egypt, where gold masks, statues, coins, and much jewelry was archeologically excavated. Gold has been used for coinage throughout the centuries, and is currently accepted internationally as a standard value. Nowadays the main use of gold is for jewelry.
Due to gold&rsquos distinctive properties as a metal, it has several industrial uses. It is also used for photography, dentistry, coloring, and being studied for treatments in cancer.

Composition: Lead sulfide. May contain impurities, such as silver, arsenic, antimony, and copper.
Uses: Galena is by far the greatest ore of lead. Galena is the most common mineral containing lead, and contains mostly lead. Since the extraction process is so simple, lead has been extracted from Galena since the earliest times. Galena was also used in early radio devices. Well crystallized Galena specimens are popular collectors items.
Galena from certain regions is rich in silver. Specimens may contain as much as 20 percent silver. Because of this, silver-rich Galena is commonly an ore of silver.

Composition: Hydrous calcium sulfate
Uses: Gypsum is an industrially important mineral. It is the primary ingredient of plaster-of-Paris (finely ground Gypsum) and is also used in the production of cement. It is also the main component of sheet-rock. It is used as a flux for creating earthenware, and can be used as a fertilizer. The variety Alabaster is is carved for ornamental use, such as artistic sculptures and pottery. It is porous and is therefore easily dyed. The fibrous Satin Spar variety is sometimes cut into cabochons for collectors because of its strong cat&rsquos eye effect.
Fine Gypsum specimens are very popular among mineral collectors, especially the varieties Selenite and Desert Rose.

Composition: Iron oxide. May contain slight amounts of titanium.
Uses: Hematite is the principle ore of iron. Huge quantities are mined yearly for industrial production. It is the source for roughly 90 percent of all iron mined in the United States. Hematite was largely used in the past as a red and brown pigment, although nowadays cheaper sources have been substituted. Well formed Hematite crystals are popular among mineral collectors. Highly polished, tumbled Hematite from Brazil makes a very popular, inexpensive specimen for collectors. Hematite also has gem uses. It is cut and polished into cabochons for jewelry and ornaments, fashioned into beads for bracelets and necklaces, and carved into ornamental figures.

Composition: Iron oxide. May contain many impurities partially replacing both the first and the second iron.
Uses: Magnetite is an important ore of iron. Its perfect crystals are also famous among mineral collectors. This mineral is of scientific interest because of its special magnetic properties.

Composition:Made up almost entirely of small grains of olivine, or pyroxene may be present in appreciable amounts.
Uses: As a source of valuable ores and minerals, including chromite, platinum, nickel and precious garnet. Diamonds are obtained form mica-rich peridotite (kinmberlite) in South Africa.

Composition: Iron sulfide, sometimes containing small amounts of cobalt, nickel, silver, and gold.
Uses: Pyrite was polished by the Native Americans in the early times and used as mirrors. Today, it is used as an ornamental stone, as well as a very popular stone for the amateur collector. It is sometimes used as gemstone by being faceted and polished for use as a side jewel in a ring, necklace, or bracelet. Pyrite is many times wrongly called &ldquoMarcasite&rdquo in the gem trade. Although the mineral Marcasite has the same composition as Pyrite, it is a different mineral. Marcasite is not suitable for gem use, because it powders and may disintegrate into a powder.

Composition: Gold, with small amounts of silver sometimes also copper and iron
Uses: Gold has been used as a precious metal throughout the history of mankind. This is due to its resistance, beauty, rareness, and the fact that it is very easy to work with. In addition, in the olden days gold didn&rsquot have to be extracted, because a large amount was found in a pure state. Many gold ornaments from the past have been found. Most noted are from the tombs of the Pharaoh in Egypt, where gold masks, statues, coins, and much jewelry was archeologically excavated. Gold has been used for coinage throughout the centuries, and is currently accepted internationally as a standard value. Nowadays the main use of gold is for jewelry.
Due to gold&rsquos distinctive properties as a metal, it has several industrial uses. It is also used for photography, dentistry, coloring, and being studied for treatments in cancer.


MINERALOGICAL AND GEMOLOGICAL CHARACTERISTICS

Crystal Morphology and Structure. Tourmaline from Luc Yen is found in the form of single crystals (figure 5, left) or as multi-crystal aggregates (figure 5, center). Prismatic crystals usually show a combination of hexagonal and trigonal prisms terminated with a pyramid or pinacoid face (figure 5, left). Color-zoned crystals usually have more complex habits, with many prism faces combining to create multiple stripes parallel to the c-axis. Pink tourmaline crystals can form columnar aggregates (figure 5, center) or radiate from a central point (figure 5, right). Individual crystals can reach up to 20 cm in length (Long et al., 2013).

Lattice parameters of 14 different-colored Luc Yen tourmalines were determined (Nhung et al., 2005 2010) as follows: a = 15.824&ndash15.994 Å, c = 7.091&ndash7.208 Å, c/a = 0.445&ndash0.453 Å. Notably, three of the samples, which had a uniform dark green and dark brown color, gave the high value for the c lattice parameter (7.190&ndash7.208 Å) and the high c/a ratio (0.451&ndash0.453) that are characteristic for dravite and uvite. The 11 remaining samples, including particolor and homogeneous colored stones, had the lower values (c = 7.091&ndash7.130Å, c/a = 0.445&ndash0.448) characteristic of elbaite.

Visual Appearance and Gemological Properties. Luc Yen tourmalines come in many colors, including pink, green, yellow, orange, red, gray, brown, and black (figure 6), commonly with a mixing of hues (e.g., greenish yellow and brownish red) and a variety of tones and saturations. Many are particolor, with color zoning distributed along the c-axis (figure 6D) or from the center to the periphery (figure 7). Colorless zones are frequently found in particolor material. Sometimes the zoning creates fancy patterns, as seen in figure 8. The color distribution does not follow a predictable pattern it may be black in the center and pink in the margin, but may also be red or green in the center and green or black in the periphery. Notably, tourmaline from Minh Tien and An Phu has a wider range of color, while tourmaline from Khai Trung and Tan Lap is mainly pink or purple.

Pleochroism was observed in all samples but was most intense in green, brown, and purple stones (see table 1). The material ranged from transparent to translucent to opaque for some black, brown, and green samples. RI measurements indicated values of n&epsilon = 1.618&ndash1.628 and n&omega = 1.635&ndash1.645, with a birefringence of 0.016&ndash0.023. SG values ranged from 3.05 to 3.20. Yellow and green tourmalines measured from 3.11 to 3.20, while pink, red, orange, brown, colorless, grayish blue, and other green samples showed values from 3.05 to 3.10. These last green samples were uvite species.

All of the tourmalines were inert to long-wave UV radiation. The pink, red, brown, and black samples were inert to short-wave UV as well, though the green, yellow, and brownish yellow specimens fluoresced yellowish green (see figure 9 and table 1). No phosphorescence was observed in any of the samples.

Internal Features. Most of the Luc Yen tourmalines contained inclusions, such as the gas-filled mirror-like fractures described by Liddicoat (1990). Two-phase (gas + liquid) inclusions were the most common (figure 10, left). Growth tubes were also encountered frequently (figure 10, right). A few pink tourmaline samples contained abundant small solid inclusions of albite and tourmaline (figure 11), with albite being more common. Albite inclusions often showed twinning under a polarizing microscope with crossed polarizers. Tourmaline inclusions had needle or rod forms (figure 11, right). In one faceted green tourmaline sample, we observed reddish brown granular inclusions, presumed to be xenotime or monazite, surrounded by halo tension cracks that might have been caused by radioactive elements within the inclusions. Monazite inclusions were previously reported in a pale pink California tourmaline (see Gübelin and Koivula, 1992). Apatite, quartz, and diopside were also found in Luc Yen tourmaline (Huong et al., 2012).

Table 1 compares the gemological properties of Luc Yen tourmaline from this study with those published elsewhere in the literature.


Department of Geosciences - Field Trips

The field trips posted below illustrate just a few of the opportunities you have for hands-on learning and field experiences.

Please note: Not all field trips are offered every semester. If you are interested in participating in one of our field trips you can check out our current offering by visiting TigerEnroll then selecting the semester of interest and the Department of Geosciences.

GSCI 355 Field Trips in Geology

Recently retired Professor Dr. Neuhauser taught this series for over 30 years, continuing the tradition the geosciences department has configurated together new Professors to educate and expand the geological history of these profound and interesting sites of geoscience interest. New faculty are further adding new and improved geological sites for the students that are interested in learning about the riveting environment of geosciences. There are a number of different themes which include the traditional series of trips beginning on the FHSU campus, in Hays, and heading to Lake Wilson in Russell County, to the northern portion of Ellis County, and to the Chalk Beds in Gove County. Additional themes include: Central and NE Kansas SE Kansas the Colorado Front Range NE New Mexico/SE Colorado Hays Water Issues and even, The Geology of Wine or The Geology of Beer. Usually 3 different themes are offered through  FHSU Online in each semester. See the course schedule for upcoming trips. These courses are available as both face-to-face (real) field trips, and as virtual field trips.

All GSCI 355 face-to-face field trip courses require the following items and fees.

  • Required: Pack a lunch and dress appropriately for weather. Guidebook will cost $15.
  • Suggested: Sunscreen, bug spray, and hiking boots.
  • Optional: Hammer, hand lens, and sample bags.

GSCI 355 Field Trips in Geology - Lake Wilson
This field trip provides an overview of geology between FHSU & Lake Wilson. Participants will view and discuss the impact of the I-70 sink hole, and will complete a study of the Wilson Lake spillway. Trip includes stops at various roadcuts. Minor hiking will be involved. Vans will leave at 8:45 AM and will return the same day at 4:00 PM.

GSCI 355 Field Trips in Geology - Ellis County
This field trip focuses on the geology of Ellis County, FHSU campus, a rare volcanic ash quarry, and an introduction to local geological formations. Trip includes some fossil and mineral collecting. Minor hiking will be involved. Vans will leave at 8:45 AM, and will return the same day at 4:00 PM.

GSCI 355 Field Trips in Geology - KS Chalk Beds
This field trip to Castle Rock includes stops overlooking Hays, Cedar Bluff Reservoir, and Ogallala. Trip includes fossil and mineral collecting. Minor hiking will be involved. Vans will leave at 8:45 AM, and will return the same day at 4:00 PM.

GSCI 355 Field Trips in Geology - Colorado Front Range
This field trip explores unique geologic sites along the Colorado Front Range. Trip includes fossil and mineral collecting. Intermediate level hiking will be involved. This is a multi-day trip. Vans will typically leave at 6:45 AM on a Friday and return 9:00 pm on a Sunday. Required additional equipment and supplies: Pack food and dress appropriate for weather, tent, sleeping bag, cash for fast food travel lunch.

GSCI 355 Field Trips in Geology - Grand Canyon
This field trip focuses on exploring the activities that illustrate the different aspects and information regarding the Grand Canyon's geologic and human history. 

GSCI 355 Field Trips in Geology - Mesa Verde
This field trip focuses on exploring the activities that illustrate the different aspects and information regarding Mesa Verde's geologic and human history. 

GSCI 454 Field Studies in Geosciences (Field Camp)

An integrative geoscience capstone course involving a broad range of applied field techniques and procedures. Not only are students evaluated in the field on core courses, they will also be exposed to applied (forensic geophysics, GIS, GPS, geoarcheology, computer and environmental science technologies). Permission required to enroll. To find out more visit the Field Camp webpage.

GSCI 665 Severe Storm Observations (Storm Chasing)

Offered in early summer this course offerst the opportunity for students to view storms and learn about the dynamics of thunderstorms, the impacts of severe weather, and the geography of the central United States. Course activities include gaining experience in forecasting storms, traveling to potential storm development areas, and observing storms. Permission required to enroll. 

GSCI 651 Field Studies in Geography

A concentrated group field study stressing the environment, resources, lifestyles, and problems of a designated territory of the world. Each semester this course is taught, a different region is studied. See FHSU course listings for upcoming course offerings.

Fall 2021- National Weather Center 

This course will explore various aspects of weather prediction and includes a field trip to a weather prediction center.

Fall 2018 - Salt Mines and The Cosmoshere (11/3/18)
This field trip will explore two regional museums and the impact of both earth and cosmos on various aspects of human life and exploration. Participants will study the geography and geology of earth through exploring an underground working salt mine and touring a space museum. Contact course instructor Dr. Richard Lisichenko ([email protected]) for additional information.

  • Itinerary: Full itinerary will be available to enrolled students.
  • Fees: Admission Fees.  $55.00 (est) due to office no later than Oct. 26.
  • Qualifications: This trip may include some minor hiking.
  • Meals: You will need to bring money for meals. 
  • Weather/Climate: Come prepared for weather. You may also want to bring a light jacket as the mine can be chilly.
  • Equipment Needed: Quality walking boots/shoes (no flip flops!), clothing and other your personal items. Notebook and pencil. Camera. Money for meals. A desire to explore the earth and space around you.

Spring 2019 - Geography of Barbeque (4/12/19-4/13/19)
This field trip will explore the geography of barbeque. The four capitals of US barbecue are considered to be the Carolinas, Memphis, Texas, and Kansas City. Each region is known for it's own style, this course will explore the culinary art of barbeque and the geography of the cultures that claim it. Contact course instructor Dr. Keith Bremer ([email protected]) for additional information.

  • Itinerary: Full itinerary will be available to enrolled students.
  • Fees: Lodging fees, Fee amount $35.00 due to office no later than April 1.
  • Qualifications: This trip may include some minor hiking.
  • Lodging: Lodging will be in smaller local inns and to keep costs down rooms will be reserved to maximize occupancy to each room.
  • Meals: You will need to bring money for meals. If you have special dietary requirements please advise the instructor prior to the trip and you may want to consider bringing some of your own food. Meal sites and trip purpose will be experiencing local barbeque cuisine.
  • Weather: Come prepared for weather common to the area and time.
  • Equipment Needed: Quality walking boots/shoes (no flip flops!), clothing and other overnight personal items. Notebook and pencil. Camera. Money for meals. A taste for new experiences.
Examples of Past Trips

AAG Geography, Sustainability and GIScience (Spring 2018) - This field trip included participation in the annual meeting of the American Association of Geographers in New Orleans as well as exploration of the old south. Instructor: Dr. Grady Dixon

Geography of Kansas Brewing (Fall 2017) - This field trip explored the unique and cultural aspects of brewing beer in Kansas. Instructor: Dr. Grady Dixon

Turquoise Trail, NM (Fall 2013) - This field trip explored the area between Albuquerque and Santa Fe. This area has a cultural history rich in settlements, battles, and diversity. Participants explored the trail along which Kit Carson marched the Navajo people on their 'long walk' to incarceration at Fort Sumner. This trip offered scenic views, a study of diverse cultures, extensive history lessons, and a great outdoor opportunity. Instructor: Dr. Tom Schafer.

Mining & Prospecting Culture in the Colorado Mountains (Fall 2013) - This field trip studied the history and culture of both gold and silver mining in the Colorado mountains. Field trip includes mine and history tours. Participants also had the opportunity to experience gold panning and investigated the cultural impact of precious metal discovery on the region. Instructor: Dr. Tom Schafer

Diamond Pipes & Diamond Prospecting in the American Mid-West (Fall 2012) - This field trip gave participants the opportunity to participate in a diamond mining adventure and to investigate the cultural impact of gemstone discovery on the region around Murfressboro, AK.

Ozark National Forest (Spring 2012) - This trip was the perfect trip for anyone fascinated by mountains and the people who have both adapted to and modified the landscape of a mountainous region. Students gained experience describing and interpreting a unique geography region as they immersed themselves into the environment, hiking through stunning and thought-provoking scenery. Students practiced interpretation of physical & human landscapes through a guided hiking experience in the Ozark National Forest.

Disasters and Response: A Ground Level View (Spring 2012) - Students had the opportunity to study a recent site of a disaster, as well as the opportunity to study the on going disaster response. Instructor: Dr. Tom Schafer

Yards, Houses, & Cemeteries: Changing landscape tastes in Hays over time & space (Spring 2012) - Students practiced interpretation of physical and human landscapes through a guided experience study changing landscape tastes in Hays over time and space. Instructor: Dr. Paul Phillips

Colorado Mountain Trek/Colorado Front Range (Fall 2012, Fall 2011, Spring 2011) - Students studied Colorado's Front Range region with Dr. John Heinrichs. Participating students had the opportunity to experience and discuss the urban geography, igneous and metamorphic geology, and geomorphological features of the area while hiking through striking wilderness areas. This was the perfect trip for anyone fascinated by mountains and the people who have both adapted to and modified the landscape of a mountainous region. Students gained experience describing and interpreting a unique geography region as they were immersed into the environment, walking through downtown Denver identifying aspects of urban sprawl as well as cultural influences.

SW Oklahoma, Arbuckle Mountain Region (Fall 2011) - students studied the human landscape in the region around the Arbuckle Mountains and Anadarko Oil Bason with Dr. Tom Schafer. Participants had the opportunity to practice interpretation of physical and human landscapes through a guided experience. Field study sites included: Fort Sill Museum, Anadarko Oil Basin, Wichita Mountains, & Arbuckle Mountains.

New Mexico, Mid-Continent Volcanic Physical Geography (Spring 2010) - Students explored New Mexico's volcano region with Dr. Tom Schafer. They had the opportunity to experience and discuss the physical geography, physical geology, and affected culture of this unique area. This trip included: a visit to the Dinosaur Trackways at Clayton State Park and in-depth tour of the Capulin Volcano National Monument and surrounding region a hike at the lava flow at Black Mesa in Oklahoma and a short hike into Little Horse Mesa.


Ruby Value

Burma Ruby – Unheated

Origin and lack of treatment should be certified. Prices for oval and cushion cuts. Add up to 20% or deduct to 10% for other cutting. Add 7% to 10% for rounds, pears, marquis. Add 15% to30% for emerald cuts.

Burma Ruby – Unheated – Top Color: R 6/6

No trade data available. As of May 2015, the record price for a ruby is approximately $1.172 million per carat. ($30 million for a 25.59 carat Mogok “pigeon’s blood” ruby).

Burma Ruby - Unheated - Very Good Color: R 5/6, 7/5 slpR 5/6, 6/6, 7/5 stpR 6/6

Burma Ruby - Unheated - Good Color: R 6/5 slpR 6/5 stpR 5/6

Burma Ruby - Unheated - Good Color: R 6/5 slpR 6/5 stpR 5/6

Burma Ruby - Unheated - Fair Color: R 5/5, 6/4, 7/4 slpR 5/5, 6/4, 7/4

Ruby – Heat Treated

Prices for oval and cushion cuts. Add up to 20% or deduct to 10% for other cutting. Add 7% to 10% for rounds, pears, marquis. Add 15% to30% for emerald cuts.

Ruby – Heat Treated – Top Color: R 6/6

Not enough trade data available.

Ruby - Heat Treated - Very Good Color: R 5/6, 7/5 slpR 5/6, 6/6, 7/5 stpR 6/6

Ruby - Heat Treated - Good Color: R 6/5 slpR 6/5 stpR 5/6

Ruby - Heat Treated - Fair Color: R 5/5, 6/4, 7/4 slpR 5/5, 6/4, 7/4

Additional Ruby Shapes and Types

Cabochons

Star Ruby

Indian Rubies

Accompanying value information:

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Large, gem-quality rubies can be more valuable than comparably sized diamonds and are certainly rarer. In fact, smaller blue sapphires (1-3 cts) are relatively abundant compared to small, gem-quality rubies. As a result, even small rubies have relatively high values.

Oval-cut, purplish red ruby, 1.52 cts, 7.1 x 5.7 x 4.1 mm, unheated, Myanmar. © ARK Rare Gems. Used with permission.

The vast majority of rubies are “native cut” in their country of origin. High-value ruby rough is tightly controlled and rarely makes its way to custom cutters. Occasionally, such native stones are recut to custom proportions, albeit at a loss of weight and diameter. Custom-cut and recut stones usually have higher values per carat than native or commercial-cut stones.

This is a beautiful antique ring, but the ruby and diamonds have received native cuts. While these cuts retain much of the mass of the rough stones, the resulting gems have irregular shapes and don’t look very lively. 18k yellow gold, 1-ct ruby, and 0.15 ctw diamonds. Photo courtesy of liveauctioneers.com and Burchard Galleries.

Origin and color greatly affect the value of a ruby. For more information on ruby quality factors, consult our buying guide and appraisal guide.


Color-Change Glass as a Zultanite Imitation

Diaspore, a relatively common mineral with the chemical formula AlO(OH), is found in metamorphic bauxite deposits (A.A. Calagari and A. Abedini, &ldquoGeochemical investigations on Permo-Triassic bauxite horizon at Kanisheeteh, east of Bukan, West-Azarbaidjan, Iran,&rdquo Journal of Geochemical Exploration, Vol. 94, No. 1, 2007, pp. 1&ndash18), and usually appears as a mineral inclusion in sapphire, ruby, and spinel (V. Pardieu, &ldquoHunting for &lsquoJedi&rsquo spinel,&rdquo Spring 2014 G&G, pp. 46&ndash57 Spring 2016 GNI, pp. 98&ndash100 Summer 2016 GNI, pp. 209&ndash211). However, gem-quality transparent diaspore is rare and appears to be unique to the Ilbir Mountains area in southwest Turkey (M. Hatipoglu et al., &ldquoGem-quality transparent diaspore (zultanite) in bauxite deposits of the Ilbir Mountains, Menderes Massif, SW Turkey,&rdquo Mineralium Deposita, Vol. 45, No. 2, 2010, pp. 201&ndash205). Zultanite is the trade name of diaspore that exhibits a color-change effect the material appears yellow, pink, or green in different light sources. Zultanite has only been found in the Anatolian Mountains of Turkey (M. Hatipoglu and M. Akgun, &ldquoZultanite, or colour-change diaspore from the Milas (Mugla) region, Turkey,&rdquo Australian Gemmologist, Vol. 23, 2009, pp. 558&ndash562).

The Gemological Institute of China University of Geosciences in Beijing recently received two samples, an unmounted 8.44 ct 10 × 12 mm faceted pear-shaped specimen and a ring with an 8 × 10 mm faceted oval, that displayed a color-change effect. The material was reportedly purchased from Turkey as Zultanite, a designation the client wished to confirm. Both samples were yellowish green in fluorescent light with a color temperature of 5500 K (figure 1, left) and brownish yellow in incandescent light (figure 1, right). The specimens were fairly clean, with no obvious inclusions and no obvious scratches on the surface. Facet junctions were generally smooth, with small chips. A series of absorption lines related to rare earth elements (REE) were observed by a handheld prism spectroscope. These properties, along with electron microprobe analysis, indicated that the two samples were not diaspore or any other natural material, but rather man-made glass. The infrared spectrum of the unmounted specimen, with peaks at 1037, 462, 443, and 430 cm &ndash1 , confirmed the material was glass.

LA-ICP-MS data of three points on the loose sample are reported in table 1. The main trace elements were Nd (102,792 average ppmw) and Pr (68,500 average ppmw), both rare earth elements. Other REE included Gd (1473 average ppmw) and Ce (135 average ppmw). Nd and Pr are the chromophores that cause color change in material such as synthetic cubic zirconia (Fall 2015 GNI, pp. 340&ndash341).

The visible-range absorption spectrum of the loose material (figure 2) showed a typical spectrum of glass with rare earth elements. This spectrum showed bands at 443, 479, 529, and 587 nm. The bands at 443, 479, and 529 nm indicate the presence of Pr 3+ , which caused the green or yellowish green color. The brownish yellow color is related to the 587 nm absorption peak, which is induced by Nd 3+ .


Gemstone Treatment and Enhancement

Any process other than cutting and polishing that improves the appearance color, clarity, phenomena or durability called enhancement.

Beauty enhancing treatments can produce remarkable results. Less expensive materials can be transformed into beautiful gemstones. Gemstones are treated in different ways to improve their appearance and make them more marketable. The most famous method of gemstone treatment is heat treatment.

Heating method helps in improving or removing the gemstone colour. Tourmalines are frequently heated to lighten the color. Blue zircons are usually heated and the resulting color is permanent. Since heating is generally permanent, heated stones do not require special care.

Bleaching, coating, dyeing, filling, impregnation and waxing methods are used for Semi-permanent or temporary gem enhancement, However flux healing, fracture filling, heat treatment, irradiation, lattice diffusion and lasering can make permanent effects on gemstones.

Oiling process is used to enhance the clarity of Ruby, sapphire, Tourmaline and emeralds. Oil is applied to the stone by pressure plus vacuum to enhance its clarity through different lubricating machines and these machine can be used at home, in the office or anywhere because of it's simplicity way of use.

For some stones treatment or enhancement can reduce its value?

For example, a large, untreated, (color unchanged) stone is much more desirable on the marketplace than a similarly "treated" stone and will never lose its color or beauty.

There is nothing intrinsically wrong with gem enhancements as long as you are made aware of their use. You can always get the better results by giving the right treatment to your gemstones.

Visit http://gemsmins.com for rough and cut gemstones, minerals and specimens collection.
For gemstone articles visit http://gemsmins.com/blog

We are registered with all representative trade organizations and government Institutions as gemstone and Minerals exporters. Our Focus in the gemstone industry is to bring out the Undiscovered and unique Stones found in this part of the world.


Watch the video: ΠΕΡΙ ΛΙΘΩΝ Κ ΚΡΥΣΤΑΛΛΩΝ (October 2021).