Spodumene

spodumene

eucryptite

lithium

kunzite

Images

Formula: LiAlSi₂O₆
Inosilicate (chain silicate), clinopyroxene subgroup, pyroxene group, lithium-bearing mineral
Kunzite is a pink gem variety of spodumene
Crystal System: Monoclinic
Specific gravity: 3.1 to 3.2 measured, 3.184 calculated
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
Common impurities: Fe,Mn,Mg,Ca,Na,K,H₂O
Environments:

Pegmatites

Spodumene is found almost exclusively as a primary mineral in lithium-rich pegmatites.

Localities

At the Hayman Hill deposit, Charlotte County, New Brunswick, Canada, Spodumene-bearing pegmatite dikes were discovered in 2025, with the mineral assemblage spodumene, albite, muscovite, quartz, garnet, schorl, columbite and Li-phosphate.
The spodumene pegmatite dikes intruded thick-bedded, metasedimentary rocks that are mainly fine- to coarse- grained quartz arenite interlayered with silty shale and black carbonaceous shale. Metamorphic mineral assemblages (such as staurolite, andalusite and cordierite) in the muddy layers indicate amphibolite facies metamorphism. The pegmatite dikes are irregularly zoned with areas that have millimetre- to centimetre- sized spodumene, quartz, garnet and schorl surrounding large (decimetre-sized) feldspar crystals. All dikes share a similar mineral assemblage of quartz, feldspar, spodumene, muscovite, orange garnet and black to dark blue schorl. Other trace minerals, columbite, zircon and Li-phosphate, were identified only in thin section. The Hayman Hill pegmatite dikes are classified as albite-spodumene subtype of the lithium - cesium - tantalum (LCT) pegmatite family.
The acicular spodumene in the spodumene-rich zones is white to buff brown, 5 to 15 cm in length and 1 to 2 cm wide.
The Hayman Hill area also hosts several pegmatite dikes that do not contain spodumene. (CJMP 64.27-34).

The Peatfold pegmatite at Glenbuchat, Strathdon, Aberdeenshire, Scotland, UK, shows a distinctly zoned structure, broadly symmetrical around a central core of bright purple mica, probably lepidolite. The spodumene lens contains striated, fractured intergrown crystals of spodumene, associated with plentiful tourmaline. This occurrence of spodumene is thought to be the first substantiated report of the mineral from Scotland. (JRS 20.30-33).

At the White Picacho District, Arizona, USA, the alteration sequence for spodumene is
spodumene → eucryptite + albite → muscovite + albite → muscovite
(AM 67: 97-113).
The zoning sequence within the pegmatite goes from spodumene + quartz to spodumene + montebrasite + quartz to montebrasite + quartz (R&M 92.2.151)

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, spodumene crystals to 50 cm are associated with amblygonite-montebrasite, pollucite and alkali-rich beryl. The Emmons pegmatite is an example of a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.515). Talc pseudomorphs after spodumene have been found here (KL p235).

At Plumbago Mountain, Newry, Oxford County, Maine, USA, excavations and core-drilling have exposed a new albite-quartz-spodumene pegmatite, the Plumbago North pegmatite. It is spodumene-rich with more than 50 percent spodumene in some of the upper portions of the pegmatite. The exposed portion of the pegmatite is composed principally of quartz, albite, muscovite and spodumene. Microcline is sparse and occurs in the spodumene zone and rare miarolitic cavities. Montebrasite, beryl, cassiterite, almandine-spessartine series garnets, fluorapatite and columbite-group species are also present. Schorl, lepidolite and pollucite are rare. Columbite-group minerals include columbite-(Fe), columbite-(Mn) and tapiolite-(Fe). Triphylite pods to 50 cm across with associated iron-dominant secondary phosphate species are scattered across the spodumene-rich zone. Spodumene and montebrasite occur in gigantic crystals. One spodumene crystal exceeded 11 meters in length, and crystals in excess of 2 meters in length are common. Montebrasite also occurs in very large single crystal masses, with some exceeding 1.5 meters across (R&M 97.3.276).

Alteration

petalite to spodumene and quartz
LiAlSi₄O₁₀ ⇌ LiAlSi₂O₆ + 2SiO₂
(DHZ 4 p274)

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 (AM 67: 97-113).

spodumene and Na⁺ to eucryptite, albite and Li⁺
2LiAlSi₂O₆ + Na⁺ → LiAlSiO₄ + NaAlSi₃O₈ + Li⁺
Whether spodumene breaks down into albite or into albite or into eucryptite and albite depends largely on the presence or absence of quartz (AM 67: 97-113).

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 (AM 67: 97-113).

Back to Minerals