Twinning is common and pervasive so that in labradorite it produces a layered or stacked effect. The twin layers are typically only fractions of millimeters to several millimeters thick. Crystals of labradorite are found imbedded in gabbros and other mafic igneous rocks of low silica content. In anorthosites, labradorite is a main constituent. Cleavage is perfect in one and good in another direction forming nearly right angled prisms.
Fracture is conchoidal.
Hardness is 6 - 6.5. Streak is white. Associated Minerals are biotite , pyroxene and hornblende . Play of colors called labradorescence seen from certain directions can cause flashes of blue, violet and green and sometimes orange and yellow. Notable Occurrences include Labrador, Canada and Scandinavian Pennisula.