cryptocrystallineadj.
/ˌkrɪptə(ʊ)ˈkrɪstəlʌɪn/, /ˌkrɪptə(ʊ)ˈkrɪstl̩ʌɪn/, U.S. /ˌkrɪptəˈkrɪstəˌlaɪn/, /ˌkrɪptəˈkrɪstələn/ Chiefly Mineralogy.
Having a crystalline structure visible only under high magnification.
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the world > the earth > minerals > mineral structure or appearance > [adjective] > crystalline
crystalline1665
cryptocrystalline1849
holocrystalline1884
the world > matter > chemistry > crystallography (general) > crystal (general) > crystal irregularities > [adjective] > indistinctly or imperfectly crystalline
cryptocrystalline1849
1849 J. Nicol Man. Mineral. i. i. 47 In the third, the different parts are so minute, that even though they may be crystalline in structure, yet this cannot be discerned, and they have therefore been named crypto-crystalline.
1880 Encycl. Brit. XI. 634/1 A cryptocrystalline variety of quartz.
1920 A. Holmes Nomencl. Petrol. 175 Palagonite is a soft, brown or greenish-black cryptocrystalline substance.
1970 E. Bruton Diamonds (1978) xvii. 379 If there are no outward faces or edges to define separate crystals,..the mass is then more a cryptocrystalline mass than a crystal aggregate.
2007 New Yorker 12 Mar. 71/1 Like chert, agate, jasper, and chalcedony, flint is cryptocrystalline quartz.
This entry has been updated (OED Third Edition, June 2011; most recently modified version published online March 2022).
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adj.1849