achroiten.
/ˈakrəʊʌɪt/, /ˈeɪkrəʊʌɪt/, U.S. /ˈækrəwaɪt/, /ˈeɪkrəwaɪt/ Mineralogy.
A colourless variety of tourmaline.
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the world > the earth > minerals > types of mineral > silicates > cyclosilicates > [noun] > tourmaline > others
red tourmaline1768
rubellite1794
siberite1802
indicolite1808
zeuxite1836
achroite1850
1850 Ann. Rep. Progress Chem. 1847–8 2 380 Hermann..has been led by his analysis of tourmaline to assume that this mineral occurs of three fundamental compositions,..namely, as schorl, achroite, and rubellite.
1850 J. D. Dana Syst. Mineral. (ed. 3) v. 364 Tourmaline... White specimens (Achroite) come from St. Gothard, Siberia and Elba.
1904 Science 12 Feb. 267/2 The tourmalines are mostly pale pink... Several good achroites have also been found.
1966 R. Webster Pract. Gemmol. (ed. 4) xv. 149 Brown tourmaline loses its colour by heat, producing the colourless variety—achroite.
2005 Rocks & Minerals (Nexis) 1 Nov. 396 In 1871 Hamlin blasted open a large pocket and discovered several large achroite (colorless tourmaline) crystals.
This entry has been updated (OED Third Edition, September 2009; most recently modified version published online December 2021).
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n.1850