Enhancements
Bi-color sapphire is always heat treated to produce, intensify or lighten color and/or improve color uniformity and appearance.
More information on gemstone enhancements.
Bi-Color Sapphire ...
Fine blue tourmalines (indicolites), blue/green, bi-color, parti color can also command good prices. Pink and green tourmaline are now widely available and are especially popular in designer jewelry.
Bi-color tourmaline
Mentioned in early 20th century gemological texts, it was not until the 1970’s that bi-color tourmaline lent its charm to jewelry.
Bi-color A gemstone exhibiting two color zones, such as ametrine or many tourmalines.
Bi-Colored & Watermelon Tourmaline - The Rainbow Gem
Multicolored, bicolor, and tricolor tourmaline with irregular zones, or bands of color are generically identified by the gem trade as litticoatite (see "Litticoatite" section above), ...
[Bi-colored Mexican opal, contra-luz Mexican opal]
Value
The most desirable pieces are nearly completely transparent and, when colored, show a strong, highly saturated hue.
Bi-colored and multicoloured tourmalines may be green at one end and pink at the other, watermelon tourmalines are green on the outside and pink on the inside.
Bi-color: More than one color in the same stone
Chrome: Intense green, colored by chromium and/or vanadium
Indicolite: Blue
Paraíba: Electric blue to green, colored by copper
Rubellite: Red
Watermelon: Pink in the center, green at the edge ...
The bi-color tourmaline displays two or more colors in one stone. Watermelon tourmaline is really beautiful to see. It is a bi-color stone that has green skin and red core. This stone is often cut in slices.
Ametrine is a bi-color variety that is part amethyst colored and part citrine colored. It was first discovered in Bolivia. Generally ametrine is cut into octagon or emerald cut shapes to emphasize the two colors.
Ametrine is a bi-color variety of quartz. It is a combination of amethyst and citrine within a single crystal. The primary source of this gemstone is the Anahí mine in Bolivia.
amorphous ...
Ametrine:A variety of quartz where yellow or orange citrine and purple amethyst occur together in bi-color crystals. Ametrine is primarily mined in Brazil although Russia is known for producing synthetic equivalents.
Ametrine is a bi-color yellow and purple quartz that is formed when amethyst and citrine colors are found in the same crystal of quartz. The Anahi Mine in Bolivia is the major world producer of ametrine.
This is a bi-color variety of quartz contining both amethyst and citrine colors. The stone is usually cut in facets in a rectangular shape to show both the yellow and purple colors. The Anahi Mine in Bolivia is the major source for ametrine.
Gems like orange-pink Padparadscha sapphire or blue green Paraiba tourmaline or bi-color alexandrite are celebrated for their exquisite colors.
Color: Orange, red-brown, green, or bi-color with hematite or goethite sparkling inclusions
Hardness: 6 to 6.5
Transparency: Translucent, opaque
Can be found in India, Canada, Madagascar, Russia, the United States, and Norway ...
Axinite: An unusual, lustrous stone that is bi-colored in brown, yellow, blue, green or gray. Violet axinite, from Tasmania in Australia, is rare. It is used only as a mineral specimen and not in jewelry.
Citrine crystals may form together with Amethyst or Smoky Quartz to form a Bi-colored Quartz called Ametrine. The name comes from the French word for lemon, citron.
Cloisonné ...
Honorable Mention
Nancy Attaway
High Country Gems
5.85 ct. bi-color Montana Sapphire.
Not only does tourmaline occur in a spectacular range of colors, but it also combines those colors in a single gemstone called "bi-color" or "parti-color" tourmaline.
The adjectives bi-color or parti-colored describe single stones or crystals that show two (bi-) or more (parti-) colors that are not concentrically arranged.
Unlimited, yet rare color mixes in blue-greens, yellow-browns, purplish-greens, grayish-blues, golden-browns, bi-colored (two colors separated within the same stone), pinkish-browns and all other colors imaginable can be found.
Some faceted tourmalines show color changes from top to bottom. Most often these stones are cut into long, rectangular shapes and may display two or more color changes down their long axis. They are usually called bi-colored or tri-colored stones.
Paraiba tourmalines, particularly those from Paraiba, Brazil
Copper bearing gems from Mozambique and Nigeria: recent production has lagged at these sources
Strong color tourmalines from limited, high quality pockets
Bi-color and cat's eye ...
from metal, marble or any hard stone, but are mainly made from glass rods which are cut with a blade and hammer and termed smalti. The colors of these smalti are almost limitless and are produced in Venice. The smalti which are produced in bi-colors ...
You might be surprised to find that sapphire is one of the few gems that occur in every color imaginable. Some sapphires even have two or three different colors in one stone, these are referred to as bi-color or parti-color! ...
Often bi-colored or tricolored. Sometimes displays plieochroism or chatoyancy. Tourmaline has a hardness of 7-7.5.
Troy Ounce
The unit of measurement used in apothecary and in precious metal markets.
 See also: Color, Stone, Gemstone, Crystal, Cut
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