The Probert Encyclopaedia of Rocks & Minerals

MICROCLINE

Microcline is a mineral with the formulae KAlSi3O8 and a relative hardness of 7. It has the same composition as orthoclase but is distinguished by triclinic twinning (usually requiring a microscope to detect). If a feldspar is a deep green it is microcline - and sometimes called 'amazon stone' or amazonite after the Amazon river. It is recognisable from plagioclase by a lack of striations.
Research Microcline