Kunzite

Spodumene · LiAlSi₂O₆. Colors: pink to violetish purple.

Brief us for this stone In the encyclopedia

Mohs: 6.5–7
RI: 1.66–1.676
SG: 3.18
Crystal system: monoclinic

(Fig. 01)Stone record

Kunzite at a glance.

Kunzite specimen — Photo: Smithsonian NMNH · CC0

Species: Spodumene
Formula: LiAlSi₂O₆
Crystal system: monoclinic
Mohs: 6.5–7
RI: 1.66–1.676
SG: 3.18
Colors: pink to violetish purple

(Fig. 02)In the encyclopedia4

What the encyclopedia says.

4 passages, quoted as published. Each links to the full entry and the sources of its chapter.

02.12 · Stones
Other transparent gems: tanzanite to spodumene
Peridot is gem olivine, colored yellowish green by the iron in its composition, and occurs in basalts, in mantle rocks pushed to the surface and, rarely, in meteorites. Iolite, gem cordierite, is strongly pleochroic. Kunzite is the pink to violetish purple variety of spodumene, LiAlSi₂O₆, colored by manganese and recognized around 1902. Green hiddenite and yellow triphane are the other spodumene varieties.
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03.02 · Science
Hardness, toughness, cleavage and stability
Toughness is resistance to breaking and chipping, and it is independent of hardness. Jadeite rates 6.5 to 7 and nephrite 6 to 6.5, yet both are extremely tough, which is why Neolithic knives and axe heads were often made of nephrite. Diamond, the hardest natural gem, can still split under a sharp blow: it has four perfect cleavage directions, parallel to its triangular octahedral faces. Topaz has one perfect cleavage, on {001}, and kunzite two. Where no cleavage exists a stone breaks by fracture; quartz and glass show curved, shell-like conchoidal fracture.
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03.02 · Science
Hardness, toughness, cleavage and stability
Stability is resistance to heat, light and chemicals. Opal holds up to 20% water, and losing it shrinks the silica and can craze the surface; some kunzite fades in strong light, and pearls are etched by acids.
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04.03 · Geology
Pegmatites
Well-known pegmatite gem districts include Minas Gerais in Brazil, Madagascar, the Skardu district of Pakistan and San Diego County in California, where the Oceanview mine still yields kunzite. Pegmatites have produced some of the largest crystals known, with spodumene and beryl reported at 10 m or more in length.
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