OLIGOCLASE

noun

13 Scrabble

17 WWF

O 1

L 1

I 1

G 2

O 1

C 3

L 1

A 1

S 1

E 1

Definition

A plagioclase feldspar, the second member of the Albite-Anorthite solid solution series. Primarily found as small crystals in impure marble. Oligoclase contains a small amount of calcium substituting for some of the sodium in its formula. Oligoclase with reddish-golden inclusions found in Norway and Canada is called sunstone.