was the key to their success. Why?.
Hemimorphite
Hemimorphite has an unusual characteristic: a change in temperature or pressure induces an electrical charge in the
Diamond
Advertising tells us that a diamond is a rare and valuable thing to possess. While it cannot be disputed that white
Corundum
The most important of the gem families, corundum provides us with two of the best-known stones: ruby and sapphire. The
Faceted Square Cuts
The second group of faceted cuts includes straight-sided girdle shapes: squares, rectangles, octagons, triangles,
Emerald
The chromium and vanadium present in emerald produce its vibrant colour, which is stable against light and heat and so
Sillimanite
For some time, this tough, durable gemstone has been either considered a collector's stone or used industrially (in the
Sphene
Sphene is highly regarded as a gemstone by collectors, but scarcity has kept it out of the commercial market until now.