For those sharing my intrigue with unusual gems & minerals, I have
composed this on colour change Diaspore from Turkey.
This stone has several fascinating attributes that enhance its
potency as well as differenciate it from other gems. Diaspore is
composed of aluminum hydroxide with trace elements of chromium,
iron, occasionally manganese, and titanium. It exhibits
photochromism, which in English means various light sources will
produce different colour changes. Stones present green in daylight
and change to light peach, rose, or wine in incandescent lighting.
The composition and amounts of trace elements control the severity
of color change and the play of tones manifested in mixed lighting.
It has the ability to show three distinct colours when viewed at
different angles (Trichroic) It is doubly refractive, reflective,
biaxial, has a hardness of 6.5-7, refractive index of 1.74-1.77,
Specific gravity 3.40-4.0, density 3.3-3.5. Its crystal system is
Orthorombic. It is associated with boehmite and gibbsite as a
constituent of some bauxites. It is stable under metamorphic
conditions and sometimes is associated with corundum and magnatite
in emery deposits in the amphibolite facies. It can also be found
in marble. For those faceters looking for a challenge, you will
find it with this one. It has a perfect clevage and can be a bit
unruly to work with but the finished product is worth the effort.
A few cautions: It is extremely heat sensitive, must be cold
dopped, and laps must remain cool at all times, especially during
Victoria’s Sensual Gems
P.O. Box 151 Freidensburg ,Pa. 17933