Spodumene

LiAlSi2O6

Origin of Name : From the Greek word spodoumenos, meaning “ashes.” Hand Specimen Identification Spodumene is typically found in pegmatites where it may  form very large crystals. Prismatic cleavage,hardness, color, and association help identify it, but it may be difficult to tell from feldspar or scapolite. it often has the appearance of a log or of petrified wood.
Physical Properties
hardness 6 1/2 to 7
specific gravity 3.15
cleavage/fracture two perfect prismatic {110}/uneven
luster/transparency vitreous/transparent to translucent

color: highly variable: colorless,white, gray, pink, green,yellow, purple, or tan

streak: white
Optical Properties
Spodumene is similar to other clinopyroxenes in thinsection. Its occurrence in pegmatites and its small
extinction angle help identify it. Biaxial, , , , , 2V =60° to 80°.Crystallography Monoclinic, a = 9.52, b = 8.32, c = 5.25,,Z = 4; space group ; point group .
Habit Prismatic crystals with well-developed {100} faces showing vertical striations are common. Crystals are
often polysynthetically twinned and may be very large. In some pegmatites they are tens of meters long. Spodumene also occurs as cleavable masses.
Structure and Composition
Spodumene is a pyroxene with structure similar to that of diopside. Minor Na substitutes for Li, Fe, Ca, Mn,
Mg, and rare earths are also present in small amounts.

Occurrence and Associations
Spodumene is found in granitic pegmatites, where it associates with K-feldspar, muscovite, quartz, tourmaline,
beryl, and lepidolite.Varieties Hiddenite is a name given to emerald-green spodumene; kunzite to lilac/pink spodumene; and triphane to colorless or yellow spodumene.
Related Minerals
Spodumene is similar to other pyroxenes . It is similar in composition to eucryptite,LiAlSiO4.

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4 comments

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