Roger Weller, geology instructor
Labradorite is a plagioclase feldspar with a composition ranging from 50% to
70% albite feldspar (the sodium end member of the plagioclase family) and 50% to
70% anorthite (the calcium end member). One of the special identifying
characteristics of labradorite is a spectacular display of colors when the mineral is
viewed at certain angles; this property is referred to as "schiller". Schiller is largely
due to the interference of light caused by the reflection from thin lamellar
inclusions of various minerals. Blue and green are the most common colors, but
red, yellow, and gray are also common.
Photo is copyright free for non-commercial educational uses.
Just credit photo to R.Weller/Cochise College.