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Tsarstone collectors guide

Alexandrite guide forums

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<![CDATA[Change of Color


Color change garnet is one of the most rare, interesting, and phenomenal of all gemstones. The color change can be intense and equal to the color change of top quality alexandrite and fine color change garnets can easily be mistaken for alexandrite. Some of the best stones are from the deposit in Bekily, Southern Madagascar. Stones from this mine are well known for their strong alexandrite like color change.

Change of color is not the same as the changes in color with crystal orientation that affects tourmaline and iolite, which are due to the optical property called pleochroism. Only rare tourmalines, garnets and alexandrite absorb certain wavelengths of light so strongly that in sunlight and indoor light they appear different colors.



"Chatoyance" is French for cat's-eye. When impurity minerals occur in fibers, they give gemstones a silky appearance. When the fibers line up along one of the crystalline axes, a stone can be cut to display a bright reflective line—a special effect called cat's-eye.

Pictured cat's eye chrysoberyl is also known as cymophane. The name being derived from the Greek words cyma and phanes, meaning “wave” and “appearance.” Microscopic needle-like inclusions inside the stone reflect a streak of light known as the cat’s eye.

The cat's eye’s inclusions are aligned parallel to the crystallographic axis and they are always cut as cabochons with the fibrous need-like inclusions running across the narrow part of the stone as this is the only way to display the effect properly. ]]>
Topic page 1 of 1
Bibliographic details
Page title Phenomenal gemstones
Author Alan Javore
Website title Alexandrite Tsarstone Collectors Guide
Date published 18 October 2010 19:20 UTC
Date accessed 20 January 2019 23:45 UTC
Permanent link
AMA style
Alan Javore. "Phenomenal gemstones". In Alexandrite Tsarstone Collectors Guide. October 18, 2010, 19:20 UTC. Available at: Accessed January 20, 2019.
APA style
"Phenomenal gemstones". (2010, October 18). In Alexandrite Tsarstone Collectors Guide. Retrieved 23:45, January 20, 2019, from
Bluebook style
"Phenomenal gemstones", (last visited January 20, 2019).
Bluebook: Harvard JOLT style
See Alexandrite Tsarstone Collectors Guide, "Phenomenal gemstones", (Phenomenal gems - asterism, chatoyancy, color change, etc) (as of Jan. 20, 2019, 23:45 GMT).
CBE/CSE style
Alan Javore. "Phenomenal gemstones". In Alexandrite Tsarstone Collectors Guide. 2010 Oct 18, 19:20 UTC.[Internet], Alexandrite Tsarstone Collectors Guide; 2010 Oct 18, 19:20 UTC [cited 2019 Jan 20]. Available from:
Chicago style
Alan Javore, "Phenomenal gemstones",, (accessed January 20, 2019).
MLA style
"Phenomenal gemstones". Alexandrite Tsarstone Collectors Guide. 18 Oct 2010, 19:20 UTC. 20 Jan 2019
MHRA style
Alan Javore, "Phenomenal gemstones", Alexandrite Tsarstone Collectors Guide, 18 October 2010, 19:20 UTC, [accessed 20 January 2019].
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