A form of alkali feldspar, microcline may be colorless, while, yellow, pink, red, grey, green, or blue-green. I However, the semi-opaque, bine-green variety called amazonite (named after the Amazon River) is most commonly used in jewellery, and may be cut, usually en cabochon up 10 almost any size. Its striking color is due to the presence of lead.

The most important source of amazonite is in India. Other localities include the USA, Canada, the former USSR, Madagascar, Tanzania and Namibia.

Although microcline has the same composition as orthoclase, its crystal structure is triclinic.