What is "spectrolite"

n. a rare variety of labradorite feldspar, raning in colors from blue to red.

Spectrolite is a less common variety of labradorite feldspar.

Spectrolite exhibits a richer range of colors than labradorite (that shows only tones of blue-grey-green) and high labradorescence. Spectrolite was initially a brand name for material mined in Finland, but is sometimes incorrectly used to describe labradorite whenever a richer display of colors is present, regardless of locality: for example, labradorite with the spectrolite play of colors has also reported from Madagascar. The difference between Finnish spectrolite and other labradorites is that crystals of the former have considerably stronger colourfulness than other labradorites, caused by the black base color of spectrolite feldspar; other labradorites have mostly a transparent base color. Spectrolite is often cut as a lapidary cabochon, similar to plain labradorite, to enhance the effect and is used as a gemstone.