dioptase

[ dahy-op-teys ]

noun

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

dioptase

/ -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

Word History and Origins

Origin of dioptase¹

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

Word History and Origins

Origin of dioptase¹

C19: from French, from Greek dia- through + optos visible

Example Sentences

He sees a thousand crystalline display cases, so clear they seem to float above the floor; inside them wait the world’s mineral treasures, harvested from every hole on the globe: dioptase and topaz and amethyst and California rubellite.

From Literature

Dioptase, dī-op′tās, n. emerald copper ore.

From Project Gutenberg

This lower degree of symmetry, which is the same as that of dioptase and phenacite, is occasionally shown by the presence of an obliquely placed rhombohedron, and also by the want of symmetry in the etching and elasticity figures on the faces of the primitive rhombohedron.

From Project Gutenberg

There are perfect cleavages parallel to the faces of a rhombohedron which truncate the polar edges of r: from the cleavage cracks internal reflections are often to be seen in the crystal, and it was on account of this that the mineral was named dioptase, by R. J. Ha�y in 1797, from διοπτεύειν, “to see into.”

From Project Gutenberg

Dioptase has occasionally been used as a gem-stone, especially in Russia and Persia; it has a fine colour, but a low degree of hardness and the transparency is imperfect.

From Project Gutenberg