search
  • English speaking customer support only

    Toll Free - USA & Canada only:
    1-800-464-1640

    International:
    +66-39303404

  • Change Language
  • USD

Untreated Gemstones

It's a fact of life in the gemstone industry that many gems are treated. The most common form of treatment is heat treatment, which is applied routinely to ruby and sapphire, and to other gems such as tanzanite, blue zircon and blue apatite. Some gems, such as blue topaz, are irradiated to produce their distinctive color; in fact it's virtually impossible to buy a blue topaz gem that has not been irradiated. Other gems, such as emerald, are treated with oils or resins to fill fractures. More recently, we've seen heat treatment with beryllium diffusion for yellow and orange sapphires, and fracture-filling with lead glass for African rubies. Sometimes it seems like the gemstone world is awash with gem treatments.

Untreated African Ruby
Untreated African Ruby

The idea of treating gems is hardly new. Pliny's Natural History, the compendium of knowledge from ancient Rome written in the first century A.D., discusses a range of techniques for altering gems, including heating, oiling, dyeing and the use of foil backings and coatings. Some of those ancient techniques were undoubtedly deceptive, but nowadays, gem treatments are just a way for the industry to meet the global demand for gemstones in the face of very limited supply.

Despite the proliferation of gem treatments, there are still many choices for buyers who insist on an untreated gem. However, there is no need to pay a fortune for very rare untreated sapphires or rubies. There are a number of gemstone varieties that combine good gemstone characteristics - hardness, durability, brilliance and clarity - with outstanding color, yet are never treated. These can be bought with confidence, knowing that they are completely natural gems. Here are our recommendations for untreated gem varieties:

Untreated Spinel Gemstones

Natural Untreated SpinelMany gem dealers consider spinel to be the finest untreated gem variety available today. It has excellent gemstone characteristics, such as a hardness of 8 on the Mohs scale, and excellent clarity and dispersion (fire). Spinel has often been confused with fine ruby and sapphire. Additionally, a wide range of colors are available, including red, orange, violet, blue, pink, green and silver.

Untreated Spessartite Garnet Gemstones

Untreated Spessartite Garnet Spessartite's mandarin orange and orange-red colors are unique in the gemstone world. Spessartite has a higher refractive index than sapphire, so it has superb brilliance. With a hardness of 7 to 7.5 on the Mohs scale, spessartite is hard enough for rings.

Untreated Rhodolite Garnet Gemstones

Natural Untreated Rhodolite Garnet A mixture of pyrope and almandite garnet, rhodolite is a rose-red to purple-red garnet with none of the brownish tones associated with pyrope garnet. With the good hardness, brilliance and clarity of garnet, this is a red gem suitable for all kinds of jewelry.

Untreated Tsavorite Garnet Gemstones

Untreated Tsavorite Garnet Colored by chromium and/or vanadium, fine examples of tsavorite rival emerald for intensity of green. Yet, tsavorite has better clarity and durability than emerald, and it is never treated. Due to its rarity, tsavorite is difficult to find in large sizes.

Untreated Tourmaline Gemstones

Fine Natural Tourmaline Tourmaline provides the greatest selection of colors in any untreated gemstone. In addition to its vitreous luster and excellent clarity, tourmaline can often be found in large sizes at affordable prices. It has become our best-selling gemstone.

Untreated Peridot Gemstones

Natural Untreated Peridot Peridot is an idiochromatic gem, meaning that its color is derived from its basic chemical composition, not from trace impurities. This means it only occurs in shades of green. It also means that its color cannot be modified by any form of treatment.

Untreated Orange, Brown, and Rose Zircon Gemstones

Rare Untreated Pink Rose Zircon While the popular blue zircon is heat treated, there are natural zircon gems that are not treated in any way. These include brown, rose, rose-orange and golden orange zircon gemstones. Note that yellow and white zircon is almost always heat treated. Zircon is valued especially for its brilliance and fire. It has a refractive index higher than sapphire and spessartite garnet, and its dispersion or fire is nearly as pronounced as that of diamond.
  • First Published: March-28-2008
  • Last Updated: January-24-2019
  • © 2005-2019 GemSelect.com all rights reserved.
    Reproduction (text or graphics) without the express written consent of GemSelect.com (SETT Company Ltd.) is strictly prohibited.
Popular Gemstones
  • Shop Sapphire Gemstones Sapphire
  • Shop Emerald Gemstones Emerald
  • Shop Ruby Gemstones Ruby
  • Shop Aquamarine Gemstones Aquamarine
  • Shop Zircon Gemstones Zircon
  • Shop Opal Gemstones Opal
  • Shop Topaz Gemstones Topaz
  • Shop Tourmaline Gemstones Tourmaline
  • Shop Garnet Gemstones Garnet
  • Shop Amethyst Gemstones Amethyst
  • Shop Citrine Gemstones Citrine
  • Shop Tanzanite Gemstones Tanzanite
All Gemstones (143)
A B C D E F G H I J K L M N O P Q R S T V Z
  • Shop Actinolite Cat's Eye Gemstones Actinolite Cat's Eye
  • Shop Agate Gemstones Agate
  • Shop Agate Geode Gemstones Agate Geode
  • Shop Almandine Garnet Gemstones Almandine Garnet
  • Shop Amazonite Gemstones Amazonite
  • Shop Amethyst Gemstones Amethyst
  • Shop Amethyst Geode Gemstones Amethyst Geode
  • Shop Ametrine Gemstones Ametrine
  • Shop Ammolite Gemstones Ammolite
  • Shop Andalusite Gemstones Andalusite
  • Shop Andesine Labradorite Gemstones Andesine Labradorite
  • Shop Apatite Gemstones Apatite
  • Shop Aquamarine Gemstones Aquamarine
  • Shop Aventurine Gemstones Aventurine
  • Shop Beryl Gemstones Beryl
  • Shop Black Opal Gemstones Black Opal
  • Shop Bloodstone Gemstones Bloodstone
  • Shop Boulder Opal Gemstones Boulder Opal
  • Shop Calcite Gemstones Calcite
  • Shop Carnelian Gemstones Carnelian
  • Shop Cat's Eye Apatite Gemstones Cat's Eye Apatite
  • Shop Cat's Eye Aquamarine Gemstones Cat's Eye Aquamarine
  • Shop Cat's Eye Augite Gemstones Cat's Eye Augite
  • Shop Cat's Eye Gemstones Gemstones Cat's Eye Gemstones
  • Shop Cat's Eye Moonstone Gemstones Cat's Eye Moonstone
  • Shop Cat's Eye Opal Gemstones Cat's Eye Opal
  • Shop Cat's Eye Scapolite Gemstones Cat's Eye Scapolite
  • Shop Chalcedony Gemstones Chalcedony
  • Shop Charoite Gemstones Charoite
  • Shop Chocolate Opal Gemstones Chocolate Opal
  • Shop Chrome Diopside Gemstones Chrome Diopside
  • Shop Chrome Tourmaline Gemstones Chrome Tourmaline
  • Shop Chrysoberyl Gemstones Chrysoberyl
  • Shop Chrysocolla Gemstones Chrysocolla
  • Shop Chrysoprase Gemstones Chrysoprase
  • Shop Citrine Gemstones Citrine
  • Shop Citrine Geode Gemstones Citrine Geode
  • Shop Color-Change Diaspore Gemstones Color-Change Diaspore
  • Shop Color-Change Fluorite Gemstones Color-Change Fluorite
  • Shop Color-Change Garnet Gemstones Color-Change Garnet
  • Shop Color-Change Sapphire Gemstones Color-Change Sapphire
  • Shop Coral Gemstones Coral
  • Shop Demantoid Garnet Gemstones Demantoid Garnet
  • Shop Dendritic Agate Gemstones Dendritic Agate
  • Shop Diamond Gemstones Diamond
  • Shop Emerald Gemstones Emerald
  • Shop Enstatite Gemstones Enstatite
  • Shop Fire Agate Gemstones Fire Agate
  • Shop Fire Opal Gemstones Fire Opal
  • Shop Fluorite Gemstones Fluorite
  • Shop Fossil Coral Gemstones Fossil Coral
  • Shop Garnet Gemstones Garnet
  • Shop Golden Beryl Gemstones Golden Beryl
  • Shop Grandidierite Gemstones Grandidierite
  • Shop Grossularite Garnet Gemstones Grossularite Garnet
  • Shop Hawk's Eye Gemstones Hawk's Eye
  • Shop Hematite Gemstones Hematite
  • Shop Hemimorphite Druzy Gemstones Hemimorphite Druzy
  • Shop Hessonite Garnet Gemstones Hessonite Garnet
  • Shop Hiddenite Gemstones Hiddenite
  • Shop Howlite Gemstones Howlite
  • Shop Idocrase Gemstones Idocrase
  • Shop Imperial Topaz Gemstones Imperial Topaz
  • Shop Iolite Gemstones Iolite
  • Shop Jade Gemstones Gemstones Jade Gemstones
  • Shop Jadeite Gemstones Jadeite
  • Shop Jasper Gemstones Jasper
  • Shop Kornerupine Gemstones Kornerupine
  • Shop Kunzite Gemstones Kunzite
  • Shop Kyanite Gemstones Kyanite
  • Shop Labradorite Gemstones Labradorite
  • Shop Lapis Lazuli Gemstones Lapis Lazuli
  • Shop Larimar Gemstones Larimar
  • Shop Malachite Gemstones Malachite
  • Shop Malaya Garnet Gemstones Malaya Garnet
  • Shop Mali Garnet Gemstones Mali Garnet
  • Shop Maw-Sit-Sit Gemstones Maw-Sit-Sit
  • Shop Moonstone Gemstones Moonstone
  • Shop Morganite Gemstones Morganite
  • Shop Moss Opal Gemstones Moss Opal
  • Shop Mother of Pearl Gemstones Mother of Pearl
  • Shop Mystic Quartz Gemstones Mystic Quartz
  • Shop Mystic Topaz Gemstones Mystic Topaz
  • Shop Nuummite Gemstones Nuummite
  • Shop Obsidian Gemstones Obsidian
  • Shop Opal Gemstones Opal
  • Shop Opal Doublet Gemstones Opal Doublet
  • Shop Opal in Matrix Gemstones Opal in Matrix
  • Shop Pearl Gemstones Pearl
  • Shop Peridot Gemstones Peridot
  • Shop Pietersite Gemstones Pietersite
  • Shop Prehnite Gemstones Prehnite
  • Shop Pyrite Gemstones Pyrite
  • Shop Pyrope Garnet Gemstones Pyrope Garnet
  • Shop Quartz Gemstones Quartz
  • Shop Quartz Cat's Eye Gemstones Quartz Cat's Eye
  • Shop Quartz With Marcasite Gemstones Quartz With Marcasite
  • Shop Rainbow Moonstone Gemstones Rainbow Moonstone
  • Shop Rainbow Pyrite Gemstones Rainbow Pyrite
  • Shop Rhodochrosite Gemstones Rhodochrosite
  • Shop Rhodolite Garnet Gemstones Rhodolite Garnet
  • Shop Rhodonite Gemstones Rhodonite
  • Shop Rose Quartz Gemstones Rose Quartz
  • Shop Ruby Gemstones Ruby
  • Shop Ruby in Fuchsite Gemstones Ruby in Fuchsite
  • Shop Ruby-Zoisite Gemstones Ruby-Zoisite
  • Shop Rutile Quartz Gemstones Rutile Quartz
  • Shop Sapphire Gemstones Sapphire
  • Shop Scolecite Gemstones Scolecite
  • Shop Seraphinite Gemstones Seraphinite
  • Shop Serpentine Gemstones Serpentine
  • Shop Sillimanite Gemstones Sillimanite
  • Shop Sillimanite Cat's Eye Gemstones Sillimanite Cat's Eye
  • Shop Smithsonite Gemstones Smithsonite
  • Shop Smoky Quartz Gemstones Smoky Quartz
  • Shop Snowflake Obsidian Gemstones Snowflake Obsidian
  • Shop Sodalite Gemstones Sodalite
  • Shop Spectrolite Gemstones Spectrolite
  • Shop Spessartite Garnet Gemstones Spessartite Garnet
  • Shop Sphalerite Gemstones Sphalerite
  • Shop Sphene Gemstones Sphene
  • Shop Spinel Gemstones Spinel
  • Shop Star Diopside Gemstones Star Diopside
  • Shop Star Garnet Gemstones Star Garnet
  • Shop Star Gemstones Gemstones Star Gemstones
  • Shop Star Lemon Quartz Gemstones Star Lemon Quartz
  • Shop Star Moonstone Gemstones Star Moonstone
  • Shop Star Rose Quartz Gemstones Star Rose Quartz
  • Shop Star Ruby Gemstones Star Ruby
  • Shop Star Sapphire Gemstones Star Sapphire
  • Shop Star Sunstone Gemstones Star Sunstone
  • Shop Strawberry Quartz Gemstones Strawberry Quartz
  • Shop Sugilite Gemstones Sugilite
  • Shop Sunstone Gemstones Sunstone
  • Shop Tanzanite Gemstones Tanzanite
  • Shop Tiger's Eye Gemstones Tiger's Eye
  • Shop Tiger's Eye Matrix Gemstones Tiger's Eye Matrix
  • Shop Topaz Gemstones Topaz
  • Shop Tourmaline Gemstones Tourmaline
  • Shop Tsavorite Garnet Gemstones Tsavorite Garnet
  • Shop Turquoise Gemstones Turquoise
  • Shop Variscite Gemstones Variscite
  • Shop Zircon Gemstones Zircon
Main Categories
  • New Arrivals
  • Gemstone Lots
  • Gemstone Lots - By Piece
  • Matched Pairs
  • Cabochon Gems
  • Drilled Gems, Briolettes and Beads
  • Gemstone Carvings
  • Fancy Gemstones
  • Star Gemstones
  • Unheated Sapphire
English speaking customer support only

Toll Free - USA & Canada only:
1-800-464-1640

International:
+66-39303404

Save Money
No shipping Fees for Additional Items!
$8.90 Worldwide Shipping

Update Translation
 
Current Value
New Value
GemSelect Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
X Close Window
Colored Gemstones
Size and Weight

Gems are always measured in Millimeter (mm)

Dimensions are given as;
length x width x depth,
except for round stones which are;
diameter x depth

Select gems by size, not by weight!
Gem varieties vary in density, so carat weight is not a good indication of size

Note: 1ct = 0.2g

Size Comparison Chart