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dioptase

American  
[dahy-op-teys] / daɪˈɒp teɪs /

noun

  1. a mineral, hydrous copper silicate, CuSiO 3 ⋅H 2 O, occurring in emerald-green crystals.

dioptase British  
/ -teɪz, daɪˈɒpteɪs /

noun

  1. a green glassy mineral consisting of hydrated copper silicate in hexagonal crystalline form. Formula: Cu 6 Si 6 O 18 .6H 2 O

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of dioptase

1795–1805; < French, equivalent to di- di- 3 + Greek optasía view

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.