Spodumene
Spodumene is LiAlSi2O6, a lithium pyroxene: hardness 6.5 to 7, density 3.03 to 3.23, two cleavages near 87 degrees, 3.73% lithium. Kunzite is the pink variety.
Spodumene is lithium aluminium silicate, LiAlSi2O6, a monoclinic pyroxene: hardness 6.5 to 7, measured density 3.03 to 3.23, two good cleavages meeting at about 87 degrees. It is 3.73% lithium by mass, worked, the figure the USGS also gives, and is mined from pegmatites. Kunzite (pink) and hiddenite (green) are its gem varieties.
In short
- One species, three gem names. The September 2026 IMA-CNMNC Master List lists spodumene as LiAlSi2O6, status A, 1962 s.p., with Sweden as the country of first description. GIA calls kunzite the best-known variety of spodumene, with green hiddenite and yellow triphane the others, and attributes kunzite’s colour to trace manganese. A script over the IMA list finds no row for kunzite, hiddenite or triphane.
- Lithium, worked. LiAlSi2O6 has a formula mass of 186.09 on standard atomic weights: 3.73% lithium, or 8.03% Li2O. USGS Professional Paper 1802-K prints the same 3.73% in its table of lithium minerals. The Handbook of Mineralogy sheet’s analysis from Pala, California, has 7.79% Li2O, 97.0% of the ideal figure.
- The two-cleavage rule. The sheet gives spodumene a good cleavage on {110} in two directions that meet at about 87°. Of the five pink and green pegmatite gem minerals in the table, topaz cleaves perfectly in one direction, beryl imperfectly, elbaite very poorly and quartz rarely observably. Two flat breaks at nearly a right angle point to spodumene.
- Weight separates topaz, not tourmaline. A 20.00 g piece reads 13.40 to 13.81 g in water as spodumene and 14.27 to 14.40 g as topaz, at least 0.46 g heavier. Elbaite tourmaline reads 13.10 to 13.55 g, overlapping spodumene between 13.40 and 13.55 g: a documented failure of the scale.
- Kunzite colour can fade. GIA states that both treated and natural colour in kunzite can fade with exposure to heat and bright light, and that kunzite can be irradiated and then heat-treated to enhance its colour. The wider question is on which minerals fade in light.
| Species (gem names) | IMA formula | Hardness | Density (measured) | 20.00 g piece in water | Cleavage on the sheet | Refractive indices on the sheet | Lithium, wt% (USGS) |
|---|---|---|---|---|---|---|---|
| Spodumene (kunzite, hiddenite, triphane) | LiAlSi2O6 | 6.5 to 7 | 3.03 to 3.23 | 13.40 to 13.81 g | Good on {110}, two directions at about 87° | 1.648 to 1.679 | 3.73 |
| Elbaite (tourmaline) | Na(Al1.5Li1.5)Al6(Si6O18)(BO3)3(OH)3(OH) | 7 | 2.90 to 3.10 | 13.10 to 13.55 g | Very poor | 1.615 to 1.651 | 1.89 |
| Beryl (aquamarine, emerald) | Be3Al2(Si6O18) | 7.5 to 8 | 2.63 to 2.97 | 12.40 to 13.27 g | Imperfect on {0001} | 1.565 to 1.610 | No lithium in the formula |
| Topaz | Al2SiO4F2 | 8 | 3.49 to 3.57 | 14.27 to 14.40 g | Perfect, one direction | 1.606 to 1.644 | No lithium in the formula |
| Quartz | SiO2 | 7 | 2.65 | 12.45 g | Rarely observable | 1.544 to 1.553 | No lithium in the formula |
What is spodumene? A lithium pyroxene
The names. The IMA-CNMNC Master List writes LiAlSi2O6, status A, 1962 s.p., Sweden; the Handbook sheet writes the same formula and files spodumene in the Pyroxene group. The name, per the sheet, is from the Greek for ash-coloured, in allusion to its colour. Kunzite, hiddenite and triphane are colour varieties of this one species, not separate minerals.
What it looks like. Monoclinic, point group 2/m. Crystals are prismatic, typically flattened and striated parallel to {100}, with {100}, {010} and {110} faces, and the sheet’s size line reads to 12.5 m and 54 t. It is commonly massive. The streak is white and the lustre vitreous, pearly on cleavage. Twinning is common on {100}; mineral twinning explained covers the vocabulary. The sheet records yellow, orange or pink fluorescence under both longwave and shortwave UV.
A formula is not a species. A script over the IMA list finds two rows with the formula LiAlSi2O6: spodumene and virgilite. The virgilite sheet describes something quite different: hexagonal, crystals to 50 µm, calculated density 2.46, found as inclusions in volcanic glass near Macusani, Peru. Structure, not formula alone, names a mineral; the point is set out on crystal vs mineral.
Is spodumene a lithium ore? Lithium by mass, worked
The arithmetic, on standard atomic weights (Li 6.94, Al 26.982, Si 28.085, O 15.999). LiAlSi2O6 has a formula mass of 186.09. Lithium is 3.73% of it; expressed as oxides, 8.03% Li2O, 27.40% Al2O3 and 64.58% SiO2. That is 37.3 g of lithium in a kilogram of pure spodumene. The sheet’s Pala, California, analysis, 7.79% Li2O, works out at 3.62% lithium.
What the USGS says. USGS Professional Paper 1802-K (Bradley and others, 2017) states that lithium minerals, mainly spodumene, petalite and lepidolite, are mined from pegmatites and used mostly as feedstock for glasses and ceramics, and that the first significant lithium mining began in 1898 at the Etta pegmatite in South Dakota. Its Table K1 gives spodumene 3.73 wt% lithium, against 3.58 for lepidolite, 3.44 for amblygonite, 2.09 for petalite, 1.89 for elbaite and 5.51 for eucryptite. The lithium mica is on lepidolite.
Concentrate, worked. The USGS Mineral Commodity Summaries 2025 lithium chapter refers to spodumene concentrate graded at 6% lithium oxide. Against pure spodumene’s 8.03%, that grade carries 74.7% of the end member’s lithium oxide, or 27.9 g of lithium per kilogram, if all the lithium sits in spodumene. This page does not discuss lithium markets.
Kunzite, hiddenite and triphane: the colour varieties
Kunzite, per GIA, is the light pink to violetish purple variety of spodumene, coloured by trace manganese, first recognised as a distinct variety around 1902 and named after the gemmologist George Frederick Kunz (1856–1932). GIA’s facts panel gives refractive index 1.660 to 1.676, birefringence 0.014 to 0.016, specific gravity 3.18 and Mohs hardness 6.5 to 7.0, inside the sheet’s ranges. GIA names Afghanistan, Brazil, Madagascar and California as sources, with crystals from the Oceanview Mine in the Pala district.
Hiddenite and triphane. GIA and USGS Professional Paper 1802-K both name green hiddenite and yellow triphane as the other gem forms. The sheet’s Distribution field lists Hiddenite, Alexander County, North Carolina, as a spodumene locality; neither source here says more about the name, so neither do we.
Pleochroism and fading. The sheet records pleochroism, X purple to green and Z colourless, and GIA says kunzite’s best colour is seen down the length of the crystal. GIA also states that kunzite can be irradiated and then heat-treated to enhance its colour, and that both treated and natural colour can fade with exposure to heat and bright light. This page gives no storage or display recipe; which minerals fade in light covers the general question.
How to tell spodumene from tourmaline, topaz and beryl: the two-cleavage rule
The rule. On a broken or cleaved crystal, look for two flat, bright cleavage planes meeting at nearly a right angle. The spodumene sheet prints good cleavage on {110}, with the two directions at about 87°. Of the other four minerals in the table, none prints two such cleavages: topaz is perfect in one direction, beryl imperfect on {0001}, elbaite very poor and quartz rarely observable. GIA goes further than the sheet and calls kunzite’s two cleavage directions perfect.
Weight, as a second check. A clean 20.00 g piece reads 13.40 to 13.81 g in water as spodumene. Topaz, 14.27 to 14.40 g, is at least 0.46 g heavier; beryl, 12.40 to 13.27 g, and quartz, 12.45 g, are at least 0.13 g lighter. The method is on how to measure specific gravity at home. Hardness, 6.5 to 7 against topaz’s 8, needs a scratch, and how to test mineral hardness properly explains why that comes last.
Documented failure: tourmaline. Elbaite reads 13.10 to 13.55 g, overlapping spodumene between 13.40 and 13.55 g, so the scale cannot rule it out. Refractive index barely helps: elbaite’s highest sheet value, 1.651, sits above spodumene’s lowest, 1.648. What separates them in the hand is habit and cleavage: the elbaite sheet describes prominent trigonal prisms striated parallel to the c axis, with very poor cleavage, against spodumene’s flattened prisms and two good cleavages. The group is on tourmaline. Beryl’s page is beryl.
Where spodumene is found: South Dakota, Pala, Minas Gerais and Afghanistan
Occurrence, per the sheet: a common constituent of lithium-rich granite pegmatites, and in aplites and gneisses, with quartz, albite, petalite, eucryptite, lepidolite and beryl.
The Distribution field names: Utö, Södermanland, and the Varuträsk pegmatite near Skellefteå, Sweden; Kuortane and the Tammela district, Finland; giant crystals in the Etta mine near Keystone and elsewhere in the Black Hills, South Dakota; Hiddenite and the Foote mine, Kings Mountain, North Carolina; the Pala district, California; the Harding mine, New Mexico; the Tanco mine, Bernic Lake, Manitoba; the Urupuca mine and Resplendor, Minas Gerais, Brazil; Mawi and Kantiva, Nuristan, Afghanistan; Maharitra and Anjanabonoina, Madagascar; and Bikita, Zimbabwe. No British locality is on the sheet.
Two sizes, two sources. The sheet gives crystals to 12.5 m and 54 t. USGS Professional Paper 1802-K says the largest spodumene crystal yet found is 14 m long, from South Dakota. We print both and reconcile neither. The rest of the reference section is at the species index. We hold no catalogue and nothing here is offered for sale; the wanted list is the only commercial route.