Axinite is a brown to violet-brown, or reddish-brown bladed group of minerals composed of calcium aluminium boro-silicate, . Axinite is pyroelectric and piezoelectric.
The axinite group includes:
- Axinite-(Fe) or ferroaxinite, Ca<sub>2</sub>Fe<sup>2+</sup>Al<sub>2</sub>BOSi<sub>4</sub>O<sub>15</sub>(OH) iron rich, clove-brown, brown, plum-blue, pearl-gray
- Axinite-(Mg) or magnesioaxinite, Ca<sub>2</sub>MgAl<sub>2</sub>BOSi<sub>4</sub>O<sub>15</sub>(OH) magnesium rich, pale blue to pale violet; light brown to light pink
- Axinite-(Mn) or manganaxinite, Ca<sub>2</sub>Mn<sup>2+</sup>Al<sub>2</sub>BOSi<sub>4</sub>O<sub>15</sub>(OH) manganese rich, honey-yellow, clove-brown, brown to blue
- Tinzenite (CaFe<sup>2+</sup>Mn<sup>2+</sup>)<sub>3</sub>Al<sub>2</sub>BOSi<sub>4</sub>O<sub>15</sub>(OH) iron – manganese intermediate, yellow, brownish yellow-green
Axinite is sometimes used as a gemstone.
Gallery
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File:Axinite-64246.jpg|Clove-brown axinite crystals to 2.3 cm set atop matrix from the West Bor Pit at Dalnegorsk, Russia
File:Axinite-60191.jpg|Chloritized bladed crystals of axinite forming on adularia from the Swiss Alps
File:Tinzenite-Calcite-172430.jpg|Tinzenite on calcite, 4.5 × 3.5 × 3 cm. Wessels Mine, Kalahari manganese fields, Northern Cape Province, South Africa
File:Axinite-(Mn)-239862.jpg|Manganaxinite (Axinite-(Mn)), with sharp curving crystals to 4 cm. West Bor Pit at Dalnegorsk, Russia
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