Chatoyancy

Chatoyancy: An optical effect, possessed by certain translucent gemstones in reflecting light, in which a movable, wavy or silky sheen is concentrated in a narrow band of white light that changes its position, when the gem is turned. This is a characterized of cat's eye and some other minerals. It is caused by the reflection of light from numerous, minute, parallel fibers, cavities or elongated tubes, or needle-like inclusions within the mineral, oriented in accordance with the symmetry of the crystal. The effect may be seen in cut cabochon gems. It can be seen in certain quartz, chrysoberyl, tourmaline, moonstone, andalusite, scapolite, fibrolite, and adularia. When the needle-like or elongated cavities are parallel to more than one crystal face after being cutting cabochon, in other words, perpendicular to the plane of included materials, the stone exhibits a star effect. Also spelled chatoyance.

Bibliographic details
Page title	Definition of Chatoyancy
Author	David Weinberg
Website title	Alexandrite Tsarstone Collectors Guide
Date published	03 July 2010 04:47 UTC
Date accessed	31 May 2026 07:41 UTC
Permanent link	http://w.alexandrite.com/viewpage.html?id=GG-088-00003

AMA style: David Weinberg. "Definition of Chatoyancy". In Alexandrite Tsarstone Collectors Guide. July 03, 2010, 04:47 UTC. Available at: http://w.alexandrite.com/viewpage.html?id=GG-088-00003. Accessed May 31, 2026.
APA style: "Definition of Chatoyancy". (2010, July 03). In Alexandrite Tsarstone Collectors Guide. Retrieved 07:41, May 31, 2026, from http://w.alexandrite.com/viewpage.html?id=GG-088-00003.
Bluebook style: "Definition of Chatoyancy", http://w.alexandrite.com/viewpage.html?id=GG-088-00003 (last visited May 31, 2026).
Bluebook: Harvard JOLT style: See Alexandrite Tsarstone Collectors Guide, "Definition of Chatoyancy", http://w.alexandrite.com/viewpage.html?id=GG-088-00003 (An optical effect, possessed by certain translucent gemstones in reflecting light, in which a movable, wavy or silky sheen is concentrated in a narrow band of white light that changes its position, when the gem is turned. This is a characterized of cat's eye and some other minerals. It is caused by the reflection of light from numerous, minute, parallel fibers, cavities or elongated tubes, or needle-like inclusions within the mineral, oriented in accordance with the symmetry of the crystal. The effect may be seen in cut cabochon gems. It can be seen in certain quartz, chrysoberyl, tourmaline, moonstone, andalusite, scapolite, fibrolite, and adularia. When the needle-like or elongated cavities are parallel to more than one crystal face after being cutting cabochon, in other words, perpendicular to the plane of included materials, the stone exhibits a star effect. Also spelled chatoyance.) (as of May. 31, 2026, 07:41 GMT).
CBE/CSE style: David Weinberg. "Definition of Chatoyancy". In Alexandrite Tsarstone Collectors Guide. 2010 Jul 03, 04:47 UTC.[Internet], Alexandrite Tsarstone Collectors Guide; 2010 Jul 03, 04:47 UTC [cited 2026 May 31]. Available from: http://w.alexandrite.com/viewpage.html?id=GG-088-00003.
Chicago style: David Weinberg, "Definition of Chatoyancy", http://w.alexandrite.com/viewpage.html?id=GG-088-00003, (accessed May 31, 2026).
MLA style: "Definition of Chatoyancy". Alexandrite Tsarstone Collectors Guide. 03 Jul 2010, 04:47 UTC. 31 May 2026 http://w.alexandrite.com/viewpage.html?id=GG-088-00003
MHRA style: David Weinberg, "Definition of Chatoyancy", Alexandrite Tsarstone Collectors Guide, 03 July 2010, 04:47 UTC, http://w.alexandrite.com/viewpage.html?id=GG-088-00003 [accessed 31 May 2026].

Switch to preferred accessibility theme:

Increase or decrease the text size:

Keyboard navigation and access keys:

Alexandrite

Chatoyancy