Moonstone
Moonstone is typically colorless, but it can occur in a wide range of colors, including gray, mocha brown, yellow, orange, green, pink, blue and white. It most often exhibits a white to bluish-white sheen, but other sheens can occur such as silvery and blue-orange. Sri Lanka's moonstones with a pale blue sheen on a near-transparent body are considered most valuable. India's moonstones show cloudlike plays of light and color which are very valuable including beige brown, green, orange or simple brown. Rarer colors include blue, peach, smoke, champagne, black and red.
Some moonstones can exhibit chatoyancy. In the trade, these are known as 'cat's eye moonstone'. Other rare varieties of moonstone can occur with asterism effects. These are referred to as 'star moonstone'. Cat's eye and star moonstones are exceptionally rare and highly desirable.
Moonstone is almost always cut en cabochon to maximize the desirable effects of adularescence. With moonstone, the orientation of the cut is very important. Appropriate height of the stone is essential to display the peaked light reflection, which is why most moonstone is cut with a high dome. Cutters must locate the crystal axis exactly in the zenith of the stone in order to achieve perfect orientation which results in maximized schiller effects.