Cat's Eye Translucent yellowish chatoyant chrysoberyl is called cymophane or cat's eye. Gems lacking the silky inclusions required to produce the cat's eye effect are usually faceted. An alexandrite cat's eye is a chrysoberyl cat's eye that changes color.
Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminum. It is rare and valuable in finer grades and has been prized as a gem and ornamental stone for thousands of years owing to its unique hue. The finest of turquoise reaches a maximum hardness of just under 6, or slightly more than window glass. The luster of turquoise is typically waxy to sub vitreous, and transparency is usually opaque, but may be semi translucent in thin sections. Color is as variable as the mineral's other properties, ranging from white to a powder blue to a sky blue, and from a blue-green to a yellowish green.