periclase Min.
(ˈpɛrɪkleɪs)
[ad. mod.L. periclasia (Scacchi, 1840), erron. f. Gr. περι- very, exceedingly + κλάσις breaking, fracture: intended to refer to its very perfect cleavage. (But Gr. περίκλασις means twisting or wheeling round; brokenness, ruggedness.)]
A mineral consisting of magnesia with a small admixture of protoxide of iron, found in greenish crystals or grains, in ejected masses of crystalline limestone at Vesuvius and elsewhere. Also called periclasite (pɛˈrɪkləsaɪt).
| 1844 Dana Min. 405 Periclase..occurs in the calcareous blocks of Mont Somma. 1868 Ibid. 134 Periclasite. 1872 Nevill Catal. Min. 28 Periclasite, small but perfect crystals in calcite. |