Spectrolite

Spectrolite exhibits a richer range of colors than other labradorites as for instance in Canada or Madagascar (which show mostly tones of blue-grey-green) and high labradorescence.

Sometimes spectrolite is 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 sometimes described material from Madagascar.

[1] Finnish geologist Aarne Laitakari (1890–1975) described the peculiar stone and sought its origin for years when his son Pekka discovered a deposit at Ylämaa in south-eastern Finland, while building the Salpa Line fortifications there in 1940.

The quarrying of spectrolite began after the Second World War and became a significant local industry.

Seppo Lahti I.1989 The origin of interference colours in spectrolite (iridescent labradorite).Geologi 41.