Hexagonite is the red to pink, lilac to purple manganoan variety of tremolite. A rare amphibole, it can be transparent, translucent, and rarely opaque.
Properties Hexagonite is pleochroic, potentially displaying varying shades of blue, violet, purple, or red. It is also known as "mangan-tremolite", since the manganese imparts the mineral's unique colors. Pink, lilac, and purple are the most common colors.Hexagonite Gemstone Information; Gem Data website; accessed August 2016 Hexagonite has been successfully faceted.
Chemical formulae and history Tremolite was discovered in 1789.Tremolite on Mindat.org Hexagonite, a varietal form of tremolite, has a Mohs hardness of 5.0-6.0. Like tremolite, it is a calcium magnesium silicate hydroxide with the formula: Ca2Mg5 (Si8O22) (OH)2.Hexagonite on Mindat.org
The mineral was given the name, hexagonite, because its crystal structure was believed at one time to be hexagonal. Since then, however, it has been found to be monoclinic.
Occurrence The mineral is found primarily in the Balmat-Edwards zinc district of Edwards, St. Lawrence County, New York, United States.Balmat Hexagonite; article; July 27, 2015; Fred Haynes blog; "WCGMC Activity;" accessed Aug 2017 It was also found in the Czech Republic in the Chýnov caves.Litochleb J, Sejkora J (2007) Occurrence of tremolite-hexagonite in dolomite marbles in the Chýnov cave (southern Bohemia). Minerál 15: 124-126 (in Czech)
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