Mohs scale hardness: 7
Tiger’s eye (also spelled or known as Tiger eye, Tigers eye and Tiger Iron) is a chatoyant gemstone belong to the quartz family that is normally a metamorphic rock which is yellow to red-brown in color with silky luster. Chatoyancy, a changing in luster or color as light is reflected within the thin parallel fibrous bands. The fibrous structure of the material cause this effect to happen. The gemstones are normally cut into cabochon to best display their chatoyancy.
Tiger's Eye also shows a cat's-eye effect, but it is not the same color as the light yellow chrysoberyl. Some other gems that show a similar effect are cat's-eye tourmaline and cat's-eye opal.
How is Tiger's Eye Formed
Tigers eye is derived from crocidolite (comprised of iron & sodium), a mineral that has been oxidized to golden brown from its original blue colour and has been totally replaced by quartz. An incompletely silicified blue variant is known as Hawk’s eye.
Even though the iron & sodium dissolve (when quartz becomes imbedded between the fibers of crocidolite), traces of hydrated oxide of iron deposit between the quartz and crocidolite, creating the golden color that is common to Tiger's Eye. How golden brown, red, blue or green, Tiger's Eye and Hawk's Eye will be is determined by how much of this hydrated mineral is deposited. The rarer blue Hawk’s Eye will have only the slightest amuonts.
The varying amounts of hydrated oxide of iron cause several colors or mixes of color. It is called cat’s eye quartz when the color is greenish grey. It is called tiger’s eye when the brown stone reflects a golden yellow, and if the stone is bluish or blue gray then it is known as hawk’s eye. Mahogany or redish brown colored stones are known as ox-eye or bull’s eye.
Tiger's Eye is also a pseudomorph. Pseudomorphs (from the Greek for “false form”) form when one mineral replaces another. Since tiger-eye is a quartz replacement of crocidolite, therefore it is a pseudomorph of quartz after crocidolite. Same thing happen when quartz replaces wood to produce petrified wood.
Tiger eye is mainly composed of silicon dioxide and is coloured mainly by iron oxide. Tigers eye is also considered as the most popular chatoyant gemstone.
Tiger iron is composed of black hematite, red jasper and tigers eye. Its rippled wavy bands of color often resemble a scenic view. It has a greenish cast with shades of golden yellow, brown and reds. Marra Mamba is a form of tiger iron found in certain area of Australia near Mount Brockman. It is a rare type of tiger iron that contains shades of green, red, blue and yellow. Since the area has been mined out for so many years, therefore very little of the "true" marra mamba is available today.
Tiger Eye Treatments
Tiger’s eye is often heat treated and this is permanent therefore no extra care is needed, but just like any other gemstones that it should be avoided or protected from sharp blows or scratches and large temperature changes. Quartz dust can be hazardous to breathe according to recent research. Since the fibrous mineral in most tiger-eye has been completely replaced by quartz, it is better to take adequate precautions to avoid breathing any of the dust when working quartz or any stone.
The fibers in Tiger's Eye are very thin, may be an inch or two long. Most are only 0.000039 inches, or 0.001 millimeters, in diameter. Since tiger’s eye normally has bend or twisted fibers, sawing can be tricky and cuts must exactly parallel to the length of the fibers in order to get the full chatoyant effect. You will end up with a lifeless, dark brown to black stone if the saw cut is perpendicular to the fibers.
Red Tiger's Eye is not a natural occurrence in most cases. It is usually a result of deliberate heating. Honey-colored gems have been used to imitate those much higher valued cat’s eye chrysoberyl. The most common imitation of tiger eye is an artificial fiberoptic glass that is produced in a wide range of colours.
Tiger’s eye mostly comes from South Africa but also can be found in Burma, Australia, United States and India. Tiger’s eye is also an anniversary gemstone for the 9th wedding anniversary.
It is believed tiger’s eye has special properties:
• A healing stone for ailments of the eyes and to aid night vision.
• To reduce addiction to tobacco, alcohol and other stimulants.
• A remedy for stomach problems, digestion, ulcer, and gall bladder.
Astrologically, tiger’s eye is associated with the zodiac signs of Gemini.
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