Identifying A Colored Gemstone

One of the more challenging assignments a gemologist may have is to correctly identify colored gemstones, usually for appraisal purposes. At first thought this may seem like an easy task. As a matter of fact, there are many people who have worked in the fine jewelry industry for years that cannot correctly identify colored gemstones, I have worked with many. Identification first starts with a clean stone under a 10x gemscope. The color(s) throughout the stone and the type of inclusions offer a hint of what the stone may be. Another test using a Refractometer, which tests the gemstones ability to slow down or bend light, also aids in the id. Without getting to technical, the amount of slowing down of light it does is referred to as the Refractive Index (RI). The RI along with what was found, and not found, in the gemscope can lead to an identification. There are several other tests that a gemstone could undergo in determining what it is, but again, to keep this from getting to technical, we will just stay with these two tests as they are the most important.

In order to complete the requirements for a Colored Gemstone Graduate degree from the Gemological Institute of America, the final exam is to correctly identify twenty gemstones. A very taunting task I assure you. Let’s have some fun and see if you can pass a three stone test.  From the three color groups below, pick out a Ruby, a Sapphire, and an Emerald.

Which is the Ruby?

1-rubypyrope-garnet

 

 

 

 

Which is the Sapphire?

blue-sapphireblue-spinel kyanite

 

 

 

 

Which is the Emerald?

chrome-diopside1-emeraldtsavorite-garnet

 

 

 

 

Left to Right:                                                                                                Red: Ruby, Pyrope Garnet, Red Diamond                                                  Blue: Sapphire, Blue Spinel, Kyanite                                                       Green: Chrome Diopside, Emerald, Tsavorite Garnet

So how did you do? Pyrope Garnet, Blue Spinel, Kyanite, and Tsavorite Garnets can be found in numerous pieces of fine jewelry, usually only found in specialty/designer fine jewelry stores. A Red Diamond is extremely rare and you will probably only see one in photos. Chrome Diopside is great for the look of an Emerald but at a much lower price, however it is not commonly used.

If you are looking for a particular piece of jewelry, unless you really want a specific stone, you may want to be open minded about what Mother Nature has to offer. After all, not all blue stones are Sapphires and not all Sapphires are blue!

Treatments for Colored Gemstones

In today’s technically advanced world, all of us should be aware of exactly what we are purchasing in the gemstone world. Treatments, synthetics, and imitations can easily look like the real thing! Consumers need to know about treatments because they can easily affect the price of the gemstone and would also determine how a jewelry piece would be repaired or re-sized. I am going to discuss the different treatments so you know about them, but at the same time keep the amount of science down to a minimum (for both of our sanities)!

A treatment in colored gemstones is defined as any human-controlled process beyond cutting and polishing, that improves the appearance, durability, or value of a gem grown by Mother Nature. A treated gemstone is not a synthetic or an imitation. Those are completely ‘grown’ by man in a lab, Mother Nature had nothing to do with it. There are those that say a synthetic could be defined as “real” because it has the same chemical structure as a real gemstone, but it all goes back to the fact that they were developed by man, therefore they are synthetics. So please be aware of this whenever you are shopping for colored gemstones and yes, thanks to new technology, now even diamonds.

Any reputable and ethical dealer should disclose this information to you willingly. However I would go under the assumption that the colored gemstone you are looking at is most likely treated in some form, which may or may not be known. I have heard (but could not verify) that the amount of treated colored gemstones in the marketplace today could be as high as 80% – 95%!  The Federal Trade Commission (FTC) provides the framework of industry ethics. If you are interested in reading the full description by the US FTC, you will find it in Section 23.22 entitled “Disclosure of Treatments to Gemstones”.

There are ten types of gemstone treatments:

1: Bleaching

A treatment that uses chemicals to lighten or remove color. Cultured pearls are commonly bleached to remove dark spots and produce a uniform color.

2: Cavity Filling

Treatment that fills and seals voids to improve appearance and add weight. This treatment is often found in rubies.

3: Colorless Impregnation

Filling of pores or other openings with melted wax, resin, polymer, or plastic to improve appearance, luster and stability. Commonly used in turquoise and jadeite. Dye could be added to the filler. This would be considered two treatments, impregnation and dyeing.

4: Dyeing

A treatment that adds color or affects color by deepening it, making it more-even, or changing it. Like bleaching, dyeing is done mostly to porous gems such as jadeite, coral, and cultured pearls.

5: Fracture (Fissure) Filling

Using a filler to conceal fractures and improve the apparent clarity of a gem. The fillers include plastic, glass, polymer resins, and oils (Canadian balsam, cedarwood, and palm oil). Emeralds almost always have fracture filling as well as rubies. Due to this type of treatment, whenever having a repair done to a piece of jewelry with an emerald or ruby, always insist on the jeweler using no heat. I would even go so far as to have “no heat” written on the repair ticket. Also if a jeweler offers to clean that piece of jewelry, again insist on no heat. Most ultrasonic cleaners that jewelers use are heated.

6: Heat Treatment

Heat treatment is one of the oldest and most common of treatments. Heat treated gems were found in the tombs of ancient Egyptian kings. Heat treatment is exposing a gem to rising temperatures for the purpose of changing it’s appearance, usually color.

7: Irradiation

Exposing a gem to radiation to change or improve the color of the gem, however it is possible for the new color to revert back to the original color. Sapphires and tourmalines are likely candidates for irradiation.

8: Lattice Diffusion

The penetration of certain elements into the atomic lattice of a gemstone during heat treatment, with the objective of changing or accentuating its color.

9: Sugar and Smoke Treatments

Used on opals to bring out the play-of-color (the multiple colors usually found inside opals), sugar treatment is soaking an opal in a hot sugar solution and then sulfuric acid to deepen the color of the opal. Smoke treatment is heating a wrapped opal until smoke or ash penetrates the surface to darken the color of the opal. Of these two processes, sugar treatment is the most common. (FYI, it is a good idea to soak your opals in distilled water every once-in-a-while so they do not lose their moisture which then leads to damage.)

10: Surface Modification

Altering a gem’s appearance by applying backings, coatings, or coloring agents. The three basic methods are backing, coating, and painting. Backings to gems include silver or gold foils, fabric, paper and even colored feathers. Backings have fallen from fashion and are not commonly seen in gemstones, but are often used in costume jewelry. One gemstone that we do commonly see today that has a backing is mystic topaz. Since heat can often melt the backing, mystic topaz should not be exposed to heat. Coatings include wax, varnish, plastic, ink, and metallic compounds. Painting gem materials is another ancient practice from the Renaissance period (1300’s – 1500’s). Painting was obviously done with paint, but also ink, and nail polish.

As I am sure you have noticed, treatments are used to improve the color, clarity, and durability of a gem. Treatments are not a bad thing. Because of treatments, lesser gems can be treated to become beautiful gems and at a more affordable price, making them available to more people. If it were not for treatments, the industry would be limited to the supply of naturally created gemstones beautiful and durable enough to use as gems. In that case, the mighty and the rich would be the only ones to own them.

Gem Lady Treasures proudly uses natural gemstones, but that is not to say that at times we would use a treated gem. For example, in my quest for locating turquoise, I am looking for a turquoise that has been treated for stabilization (but not color) because it is a notoriously unstable gemstone. Of course, we would disclose the treatment.

I hope that you found this article helpful, interesting, and maybe even eye-opening. If you are interested in even more detailed information on treatments, Click Here to access “An Introduction to Gem Treatments” from GIA. Gemological Institute of America (GIA) is a world renown institute known for its research, education, and ethics in the field of gemology.

*Information for this article was provided by “Colored Stone Essentials” by GIA (11/2008).

Gem Dogs Have Arrived at Gem Lady Treasures!

I am so very excited about our new handmade gemstone pendant necklaces ~ Gem Dogs! In case you haven’t noticed, Gem Lady Treasures logo was the very first Gem Dog. We now have a fabulous selection of ‘real’ Gem Dogs that are just waiting to be adopted!

Gem Dogs are made from a natural gemstone cabochon. The head, ears, eyes, nose, feet, and tail were created by hand manipulating wire. The eyes are accented with faceted Swarovski crystals and their noses each have a Swarovski black pearl. Each Gem Dog hangs from a black vegetable dyed leather cord.

These whimsical Gem Dog pendant necklaces are adorable and perfect for any dog lover. Gem Dogs are very well behaved, good on a leash, house broken, current on their shots, and rides well in a car. They are looking for good ‘furever’ homes ~ how about yours? We really loved creating them and just know they will make someone a wonderful friend!

Turquoise Gem Dog
Turquoise Gem Dog
Dalmatian Jasper Gem Dog
Dalmatian Jasper Gem Dog
Serpentine Gem Dog
Serpentine Gem Dog

 

 

 

 

 

Purple Creek Jasper Gem Dog
Purple Creek Jasper Gem Dog
Serpentine Gem Dog
Serpentine Gem Dog
Dragon's Blood Jasper Gem Dog
Dragon’s Blood Jasper Gem Dog

Gemstones; The Beauty of Earth’s Treasures

When I was thinking about writing a blog on this particular subject, I asked several of my gemological friends what was their favorite gemstone and why. The responses I received were surprising. Only a few people were able to narrow it down to one gemstone.  Douglas Liebman, GG* and owner of an Estate Jewelry business claimed that Cats Eye Alexandrite was his favorite. “The reason being is that it combines the two most interesting phenomenon in gemstones; color change and chatoyancy (cats eye).”   Cornelis Hollander, Fine Jewelry Designer, favors Paraiba Tourmaline due to its “most beautiful neon green colors” he has ever seen.   Dana Hanna, owner of Scottsdale Sparkles admires Pink Tourmaline for its metaphysical properties. “The vibration of this lovely pink crystal brings an influx of love, joy and happiness into your life.” Everyone else had more than one. Shelly Sergent, Curator of Somewhere In The Rainbow, A Modern Gem & Jewelry Collection, stated that “I can’t answer that…impossible!!!” Shelly went on to say that she likes “bright or sultry gems that sing, dance and are sexy”.

Color Change Cat’s Eye Alexandrite
Paraiba Tourmaline
Paraiba Tourmaline
Pink Tourmaline
Pink Tourmaline

 

 

 

 

There were a couple that could narrow it down to a favorite gemstone to collect and a favorite gemstone for a piece of jewelry. William F. Ashford, ADM FGAA – Qualified Jeweller, Gemmologist, and Diamond Grader in Australia stated his favorite for jewelry was the classic diamond due to its “eternal beauty, durability and rarity”. As an Australian Gemmologist William chose Fine Precious Opal for a collection piece. It “exhibits full spectral colours rarely seen in any other natural gemstone”. Fellow Australian Donna Bollenhagen, Gemmologist and Diamond Grader, loves Tourmaline for jewelry and Rainbow Lattice Sunstone to collect. As far as collecting is concerned, Marc Allen Fleischer, GD, AJP* and Curator/Online Editor of Fleischer Museum prefers to collect specimens. His favorite specimens are the different varieties in the species of Tourmaline. Marc states that “Tourmaline is quite complex in its chemistry and is the last to crystallize in a cavity/pocket. That is how you get those wonderful color zones as the ‘soup’ of liquids and gases mix.” he further says that cutting a tourmaline loses the “termination and the striations that are observed in a natural crystal.”

Opal, Photo Courtesy of Craig Lynch
Opal, Photo Courtesy of Craig Lynch
Australian Rainbow Lattice Sunstone, Photo Courtesy of Donna Bollenhagen
Australian Rainbow Lattice Sunstone, Photo Courtesy of Donna Bollenhagen
Tourmaline Specimen, Photo Courtesy of Marc Allen Fleischer
Tourmaline Specimen, Photo Courtesy of Marc Allen Fleischer

 

 

 

 

 

Craig Lynch, GG* and Certified Insurance Appraiser is the owner of Ouellet & Lynch. He prefers to separate his favorites by color. “Red = Spinel, Green = Tsavorite (Garnet), Blue – Kashmir Sapphire, Orange – Spessartite (Garnet), Pink – Spinel, Pink/Orange – Padparadscha (Sapphire) or Topaz”. Whereas January Gaul, GG* favors gems with lots of color and movement in them such as Agates and Jaspers. I as well have two favorites, the first being Red Beryl. Red Beryl is a very rare gemstone which is principally mined in Utah, but there are also a couple of mines in New Mexico. It’s red color has been referred to as gooseberry red, carmine red, and scarlet red. My other favorite is Bi-color Imperial Topaz.

Padparadscha Sapphire
Padparadscha Sapphire
Agate
Agate
Rough Red Beryl
Rough Red Beryl

 

 

 

 

So what do you see when you study these photographs? I see gemstones with intense color, gemstones with two or more intense colors, and gemstones with phenomenon. All gemstones that Mother Nature creates are beautiful in their own right, but thanks to these gemological enthusiasts and professionals we have been exposed to some very special colored gemstones. Maybe next time when you visit a fine jewelry store, you may spend a little bit more time looking at them!

*GG: Graduate Gemologist degree Gemological Institute of America

*GD: Graduate Diamond degree Gemological Institute of America

*AJP: Accredited Jewelry Professional degree Gemological Institute of America