Moonstone occurs in a wide range of bodycolors. These include white, gray, brown, pink, orange, green, yellow and colorless. Each of these bodycolors makes a beautiful gem. The adularescence is usually a white to silvery sheen.

Rarely, colorless specimens of feldspar will produce a spectacular blue adularescence. This phenomenon is often called “blue flash” or “blue sheen” adularescence. These specimens are rare and extremely desirable.

An even rarer occurrence is moonstone that exhibits a spectrum of iridescent colors. These specimens are known as “rainbow moonstone”. This phenomenon occurs when white light is separated into its spectral colors while passing through the stone. The feldspar mineral labradorite is usually the source of these iridescent colors.

The quality of a moonstone cabochon is determined by several factors. A top-quality cabochon will have a pleasing bodycolor, excellent clarity, strong and symmetrical adularescence across the entire face of the gem, and a quality cutting job with a pleasing shape and excellent polish.