Formula: LiAlSi2O6 inosilicate (chain silicate)
pyroxene group
Kunzite is a variety of spodumene
Specific gravity: 3.1 to 3.2
Hardness: 6½ to 7
Streak: White
Colour: Colourless, white, pink and lilac (kunzite), green (hiddenite), yellow, brown
Solubility: Insoluble in hydrochloric, sulphuric and nitric acid
Environments:
Spodumene is found almost exclusively as a primary mineral in lithium-rich
pegmatites.
Alteration
At the White Picacho District, Arizona, USA, the alteration sequence for spodumene is
spodumene → eucryptite +
albite → muscovite +
albite → muscovite
petalite to spodumene and quartz
LiAlSi4O10 ⇌ LiAlSi2O6 + 2SiO2
spodumene, quartz and Na+ to albite
and Li+
LiAlSi2O6 + SiO2 + Na+ → NaAlSi3O8 +
Li+
Whether spodumene breaks down into albite or into eucryptite and albite depends largely on the presence or absence
of quartz.
spodumene and Na+ to eucryptite,
albite
and Li+
2LiAlSi2O6 + Na+ → LiAlSiO4 + NaAlSi3O8
+ Li+
Whether spodumene breaks down into albite or into eucryptite and albite depends largely on the presence or absence
of quartz.
spodumene, K+ and H+ to muscovite,
quartz and Li+
3LiAlSi2O6 + K+ + 2H+ →
KAl3Si3O10(OH)2 + 3SiO2 + 3Li+
The direct conversion of spodumene to muscovite liberates silica, but quartz is not usually present in pseudomorphs
of muscovite after spodumene, and this requires an explanation.
Common impurities: Fe,Mn,Mg,Ca,Na,K,H2O
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