| Spodumene | |
|---|---|
 Walnut Hill Pegmatite Prospect, Huntington, Hampshire County, Massachusetts, U.S. (size: 14.2 × 9.2 × 3.0 cm) | |
| General | |
| Category | Inosilicate |
| Formula | lithiumaluminium silicate, LiAl(SiO3)2 |
| IMA symbol | Spd[1] |
| Strunz classification | 9.DA.30 |
| Dana classification | 65.1.4.1 |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (sameH-M symbol) |
| Space group | C2/c |
| Unit cell | a = 9.46 Å, b = 8.39 Å c = 5.22 Å β = 110.17°; Z = 4 |
| Identification | |
| Color | Highly variable: white, colorless, gray, pink, lilac, violet, yellow and green, may be bicolored; emerald green – hiddenite; lilac – kunzite; yellow – triphane |
| Crystal habit | prismatic, generally flattened and elongated, striated parallel to {100}, commonly massive |
| Twinning | Common on {100} |
| Cleavage | Perfect prismatic, two directions {110} ∧ {110} at 87° |
| Fracture | Uneven to subconchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 6.5–7 |
| Luster | Vitreous, pearly on cleavage |
| Streak | white |
| Specific gravity | 3.03–3.23 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 1.648–1.661 nβ = 1.655–1.670 nγ = 1.662–1.679 |
| Birefringence | δ = 0.014–0.018 |
| Pleochroism | Strong in kunzite: α-purple, γ-colorless; hiddenite: α-green, γ-colorless |
| 2V angle | 54° to 69° |
| Fusibility | 3.5 |
| Solubility | insoluble |
| Other characteristics | Tenebrescence,chatoyancy |
| References | [2][3][4][5] |
Spodumene is apyroxenemineral consisting oflithiumaluminiuminosilicate,LiAl(SiO3)2, and is a commercially important source of lithium. It occurs as colorless to yellowish, purplish, or lilac kunzite (see below), or alternatively yellowish-green or emerald-greenhiddenite; it takes the form of prismatic crystals, often of great size. Single crystals of 14.3 m (47 ft) in size are reported from theBlack Hills ofSouth Dakota, United States.[6][7]
The naturally occurring low-temperature form α-spodumene is in themonoclinic system, and the high-temperature β-spodumene crystallizes in thetetragonal system. α-Spodumene converts to β-spodumene at temperatures above 900 °C.[5] Typically crystals are heavily striated along the principal axis. Crystal faces are often etched and pitted with triangular markings.[not verified in body]
Spodumene was first described in 1800 for an occurrence in thetype locality inUtö,Södermanland,Sweden. It was discovered by Brazilian naturalistJose Bonifacio de Andrada e Silva. The name is derived from theGreekspodumenos (σποδούμενος), meaning "burnt to ashes", owing to the opaque ash-grey appearance of material refined for use in industry.[2]
Spodumene occurs in lithium-richgranitepegmatites andaplites. Associated minerals includequartz,albite,petalite,eucryptite,lepidolite, andberyl.[3]
Transparent material has long been used as agemstone with varieties kunzite and hiddenite noted for their strongpleochroism. Source localities include theDemocratic Republic of Congo (DRC),Afghanistan,Australia,Brazil,Madagascar (seemining),Pakistan,Québec inCanada, andNorth Carolina andCalifornia in the U.S.
Since 2018, the DRC has been known to have the largest lithium spodumene hard-rock deposit in the world, withmining operations occurring in the central DRCterritory ofManono,Tanganyika Province.[8] As of 2021, theAustralian company AVZ Minerals[9] is developing the Manono Lithium and Tin project, and has a resource size of 400 million tonnes of high-grade low-impurity ore at 1.65%lithium oxide (Li2O)[10] spodumene hard-rock based on studies and drilling of Roche Dure, one of several pegmatites in the deposit.
Spodumene is an important source oflithium, for use inceramics,mobile phones andbatteries (including forautomotive applications),medicine,Pyroceram, and as a fluxing agent. As of 2019, around half of lithium is extracted from mineral ores, which mainly consist of spodumene. Lithium is recovered from spodumene by dissolution inacid, or extraction with other reagents, after roasting to convert it to the more reactive β-spodumene. The advantage of spodumene as a lithium source compared tobrine sources is the higher lithium concentration, but at a higher extraction cost.[11]
In 2016, the price of spodumene concentrate was forecast to be $500–600/ton for years to come.[12] However, price spiked above $800 in January 2018, and production increased more than consumption, resulting in the price declining to $400 by September 2020.[13][14]
World production of lithium via spodumene was around 80,000 metric tonnes per annum in 2018, primarily from theGreenbushespegmatite ofWestern Australia and from someChinese andChilean sources. TheTalison Minerals mine inGreenbushes, Western Australia (involvingTianqi Lithium,Albemarle Corporation, andGlobal Advanced Metals), is reported to be the world's second-largest and to have the highest grade of ore at 2.4% Li2O (2012 figures).[15]
In 2020, Australia expanded spodumene mining to become the leading lithium-producing country in the world.[16]
An important economic concentrate of spodumene, known as spodumene concentrate 6 orSC6, is a high-purity lithium ore with around 6% lithium content being produced as a raw material for the subsequent production of lithium-ion batteries for electric vehicles.[17][18]
Extraction of lithium from spodumene, often SC6, is challenging due to the tight binding of lithium in thecrystal structure.
Traditional lithium refining in the 2010s involves acidleaching of lithium-containing ores, precipitation of impurities, concentration of the lithium solution, and then conversion tolithium carbonate orlithium hydroxide. These refining methods result in significant quantities of caustic waste effluent andtailings, which are usually either highly acidic or alkali.[11] Suitable extraction reagents include alkali metal sulfates, such assodium sulfate,sodium carbonate,chlorine, orhydrofluoric acid.[19]
Another processing method relies onpyrometallurgical processing of SC6—roasting at high temperatures exceeding 800 °C (1,470 °F) to convert the spodumene from the tightly bound alpha structure to a more open beta structure from which the lithium is more easily extracted—then cooling and reacting with variousreagents in a sequence ofhydrometallurgical processing steps. Some offer the use of noncaustic reagents and result in reduced waste streams, potentially allowing the use of a closed-loop refining process.[20]Tesla has developed and, as of 2025, is operationalizing at scale, this process of lithium refinement that does not require strong acids to extract lithium from spodumene. Their method mixes sodium chloride with the open-beta-structure spodumene concentrate and water. Agitation at high temperatures produces a slurry rich in lithium that can be filtered and purified intolithium hydroxide. The sands and limestone waste products can be repurposed as construction materials. A $375 million Tesla refinery plant located on 1,200 acres inRobstown, Texas, is under construction using this process. It began partial operation in December 2024. The site was chosen for its proximity to thePort of Corpus Christi, where spodumene can easily be imported.[21]
A common form of more highly refined lithium from both of the above processes is lithium hydroxide, commonly used as an input in the battery industry to manufacturelithium-ion (Li-ion) battery cathode material.
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Hiddenite is a pale, emerald-green gem variety first reported fromAlexander County, North Carolina, U.S.[22] It was named in honor of William Earl Hidden (16 February 1853 – 12 June 1918), mining engineer, mineral collector, and mineral dealer.[23][additional citation(s) needed]
This emerald-green variety of spodumene is colored by chromium, just as foremeralds. Some green spodumene is colored with substances other than chromium; such stones tend to have a lighter color; they are not true hiddenite.
Kunzite is a purple-coloredgemstone, a variety of spodumene, with the color coming from minor to trace amounts ofmanganese. Exposure to sunlight can fade its color.[23]
Kunzite was discovered in 1902, and was named afterGeorge Frederick Kunz,Tiffany & Co's chief jeweler at the time, and a noted mineralogist.[23] It has been found in Brazil, the U.S., Canada,CIS,Mexico, Sweden, Western Australia, Afghanistan, andPakistan.[23][24]
Triphane is the name used for yellowish varieties of spodumene.[25]
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