search
  • English speaking customer support only

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

    International:
    +66-39303404

  • Change Language
  • USD

Color Change Gemstones

Natural Alexandrite
Natural Alexandrite

Gemstones that exhibit unusual optical effects are known as phenomenal gems. These effects include chatoyancy (the cat's eye effect), asterism (the star effect), adularescence (the shimmering effect, as in moonstone), play of color (as in opal) and iridescence (rainbow-like colors, as in labradorite). These remarkable phenomena have been known for centuries and gems that exhibit them are especially valuable.

More recently there is another optical effect that has drawn a lot of attention in the market - color change. Color change gemstones display different colors according to changes in lighting. The most famous of these is the rare and expensive alexandrite, a variety of chrysoberyl. However, color-change garnets and color-change sapphires have appeared on the market and show equally dramatic color changes.

Strictly speaking, the color of most gemstones varies slightly in different lighting. It is well-known that sapphire only shows its true color in natural light, and that's why the weekend gemstone market here in Chanthaburi only takes place in the open air during daylight hours. While blue sapphire suffers under incandescent lighting, the color of both ruby and yellow sapphire is enhanced by such light. That's because incandescent lighting has more energy in the warm (orange red yellow) end of the spectrum.

Color Change Garnet
Color Change Garnet

Many of these color differences are apparent only to the trained eye. But the so-called color change gems exhibit this tendency to such a dramatic degree that it is obvious to even the untrained eye. Alexandrite, for example, appears green in daylight and purplish under incandescent lighting. Color change garnet changes from bronze in daylight to a rose pink under incandescent light. Color change diaspore is usually a kiwi-green under natural light, and a brownish pink to raspberry in candlelight. Color change sapphire exhibits a range of different color changes, ranging from pink/purple to green/purple.

So why is it that only a few gemstones exhibit these dramatic color changes since nearly all gemstone color depends on the nature of the illumination? The answer is that these color change gems have two, approximately equal-sized transmission windows. A red gemstone appears red because it absorbs all frequencies of light except for red. A gemstone that absorbs all frequencies except for blue and red light will appear blue when the light is rich in blue wavelengths (e.g., fluorescent light) and red when the light is rich in red wavelengths (e.g., incandescent lighting).

  • First Published: July-11-2008
  • Last Updated: November-14-2017
  • © 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