The Gemstone Buying Guide

Gems have been attracting our attention with their captivating colors and compelling mystic allure since the dawn of civilization. Buying gemstones is like treasure hunt, full of excitement and anticipation. But inadequate knowledge and the fear of error or misrepresentation can turn the thrill into a time consuming, costly affair.

The following set of questions and answers aim to address the common concerns while buying gemstones and empower consumers to make educated buying decisions.



Question : What are the basic things I need to know before I start shopping for a colored gemstone?

Question : Which is the most important of the 4Cs?

Question : How important is clarity? Does it affect the beauty of the gemstone?

Question : Is it ok to buy treated gemstones?

Question : Is treatment necessary?

Question : Are these treatments permanent in nature?

Question : Does treatment affect a gemstone's value?

Question: Are all gemstones treated?



Question: What are the basic things I need to know before I start shopping for a colored gemstone?
Answer: Before you even begin looking for a colored gemstone, educate yourself about the 4Cs so you understand how to juggle these characteristics to achieve a high-budget look at a reasonable price.

Color
Color is the most defining characteristic of a gemstone. Most gemstones occur in a spectrum of colors, while some have more restricted palettes. As a general rule the more pure and vivid the color, more the value. For example, the most valuable sapphires have a velvety blue color with very little or no hint of green and the most precious rubies are vivid red in color, without any orange or purple visible. But if the purplish red color appeals to you, go for it. Color is a matter of aesthetics, so if a particular color speaks to you, by all means listen!
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Cut
Gemstones are cut to maintain maximum weight while exhibiting optimal color and brilliance and since each gem is unique, there aren't any rigid geometrical standards to define an ideal proportion for maximizing beauty; rather each piece is individually analyzed for its prefect cut.  A well cut gem is able to handle the play of light; the gem comes alive with life and sparkles as light dances across the facets. The gem shouldn’t have any dark lifeless areas (extinction) or flat washed out zones (window); light should be reflected consistently back to the eye accentuating the luster of the gemstone.

Don't let anyone confuse you that cut refers to the shape. Shape refers to the physical form or contour of the stone. And cut determines how well is the shape executed.


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Clarity
Gemstones naturally occur with characteristic marks, called inclusions, that were created either during the process of crystallization of the gemstone or during the polishing process. Inclusions do not necessarily diminish a colored gemstone's beauty or desirability. Unlike diamonds where the clarity standards are more stringent, gemstones even in 'heavily included' grades are desirable.
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Carat
Gemstones are typically priced on a per carat basis depending on the color and brilliance of the stone. And since gemstones rarely occur in large sizes and per-carat prices usually climb steeply as the carat weight goes up. A larger gemstone (one with a higher carat) will cost more than a cluster of smaller stones, even if the total carat weight of the stone cluster is equal to the larger stone.
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Question: Which is the most important of the 4Cs?
Answer: Color is the most defining characteristic contributing to the beauty and value of a colored gemstone. Pure hues in medium tones are the most valuable. But if darker or lighter shades appeal to you, go for it. The fact that these stones cost comparatively less is a real bonus.



Question: How important is clarity? Does it affect the beauty of the gemstone?
Answer: Clarity evaluation in colored gemstones is more relaxed than clarity evaluation in diamonds. Gemstones in ‘heavily included’ clarity grades are popularly desired as opposed to diamonds where the lowest desirable clarity grade is ‘slightly included’. Inclusions do not necessarily diminish a colored gemstone’s beauty or desirability.

In some cases inclusions can actually add to a gemstone's beauty and value. Special, needle-like inclusions cause the spectacular optical phenomenon called cat's eye and asterism displayed by chrysoberyl and corundum (sapphire and ruby) respectively. Rare and precious demantoid garnet contains unusual, golden fibrous inclusions known as horsetail.



Question: Is it ok to buy treated gemstones?
Answer: As gemstones are extracted from beneath the surface of the earth, they look like rough stones in their crude form. Since ancient times, gemstones have been treated and enhanced to bring out the aesthetic appeal of the gems. As critical as good cutting and polishing, treatments and enhancements have become an integral part of the modern gemstone industry. A vast majority of colored gems go through an enhancement process that does not diminish their natural beauty, or true worth. Heat-treating, which significantly enhances color, is the most common procedure and has a long historical precedent. Other practices include oil and resin applications to fill tiny cracks (this is especially common with rubies and emeralds), and, to a lesser extent, diffusion treatments that boost the surface color of the stone.



Question: Is treatment necessary?
Answer: Most commonly used to improve the color or beauty of the finished product, if it were not for treatments, some gemstones would not have existed at all. For instance, heating greenish brown zoisite to 600 degrees Celsius produces the much celebrated vibrant violet-blue tanzanite. The term "natural gemstones" refers to minerals formed due to natural environmental conditions for billions of years, whether or not they have been treated after mining.



Question: Are these treatments permanent in nature?
Answer: Only with the exception of oiling (treatment for emeralds), most of these industry accepted treatments are permanent in nature and stable with normal wear.



Question: Does treatment affect a gemstone's value?
Answer: No, treatment does not affect a gem’s value.  Interestingly, in some precious and semi-precious colored gemstones there is no variation between the value of treated and untreated material. In fact, treating may even increase a gems value. For example, when Zoisite is heated vibrant violet blue Tanzanite is created, commanding a far higher market price. However, high quality unheated Rubies and Sapphires are extremely rare and command a much higher market price. When purchasing high quality Rubies and Sapphires, please be aware that unheated material is almost non-existent, as a result, always purchase from a reliable supplier who guarantees their gemstones or have the seller's claim verified by a qualified expert. However, for most of us, treatments are a godsend, as they make gems more available.



Question: Are all gemstones treated?
Answer: No, not all gemstones are treated. The following gemstones are NOT treated.

Alexandrite Allanite Amblygonite Ametrine Anatase Andalusite Aventurine Axinite Azurite Malachite Boracite Brazilianite Cassiterite Chalcedony Chrome Diopside Chrysoberyl Chrysocolla Chrysoprase Cinnabar Clinohumite Danburite Diamond Enstatite (Cats Eye) Eosphorite Epidote Euclase

Gahnite Garnet Goshenite Hematite Herderite Howlite Iolite Kyanite Labradorite Larimar (Pectolite) Manganotantalite Mawsitsit Moonstone Natrolite Obsidian Oligoclase Opal Pollucite Prehnite Pyrite

Rhodonite Rutile Scapolite Scolecite Sellaite Sillimanite (Cats Eye) Sinhalite Sodalite Sphalerite Sphene Spinel Star Diopside Star Sunstone Staurolite Sunstone Tigers Eye Topaz (White) Tourmaline (Cats Eye) Tsavorite Unakite Vesuvianite Wilsonite

Common treatments
EMERALD: Usually oiled with colorless oil to improve appearance.
RUBY: Usually heated to improve color and appearance.
SAPPHIRE: Usually heated to produce intensity or light color and/or improve color uniformity.
TANZANITE: Usually heated to produce violet blue color.
AQUAMARINE: Usually heated to improve color.
BLUE TOPAZ: Usually irradiated and heated to produce blue color.
TOURMALINE: Commonly irradiated to intensify pink, red and purple color.
JADE: Commonly impregnated with colorless wax.
LAPIS LAZULI: Commonly impregnated with colorless wax or oil.
CORAL: Commonly bleached.
PEARLS: Commonly bleached to improve color and appearance.
BLACK ONYX: Always dyed.