portions of the original aragonite—which make up the nacreous layers of the pearl—had, through “induced paramorphism,” as it was known to the artful sons of Nippon, been selectively changed here and there to a different form of calcium carbonate—namely, to microscopic crystals of the doubly refracting calcite known as Iceland spar.
Wikipedia foundation.
Iceland spar — Ice land spar (Min.) A transparent variety of calcite, the best of which is obtained in Iceland. It is used for the prisms of the polariscope, because of its strong double refraction. Cf. {Calcite}. [1913 Webster] … The Collaborative International Dictionary of English
Iceland spar — n. a transparent, colorless calcite, found esp. in Iceland: it is used by opticians for making double refracting prisms … English World dictionary
Iceland spar — Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico, United States. This 35 pound (16 kg) crystal, on display at the National Museum of Natural History, is one of the largest single crystals in the United States. Iceland spar,… … Wikipedia
Iceland spar — islandiškasis špatas statusas T sritis chemija apibrėžtis Kristalinis skaidrus kalcitas, mineralas. formulė CaCO₃ atitikmenys: angl. Iceland spar rus. исландский шпат … Chemijos terminų aiškinamasis žodynas
iceland-spar — n. Calcareous spar, crystallized carbonate of lime, Iceland crystal … New dictionary of synonyms
Iceland spar — Ice′land spar′ n. mir a transparent variety of calcite that is double refracting and is used as a polarizer • Etymology: 1820–30 … From formal English to slang
Iceland spar — a transparent variety of calcite that is double refracting and is used as a polarizer. [1820 30] * * * also called Iceland Crystal, a transparent calcite used for polariscope prisms. See calcite. * * * … Universalium
Iceland spar — a crystalline form of calcium carbonate, usually found in Iceland, and used in making Nicol prisms … Medical dictionary
Iceland spar — noun Date: 1771 a birefringent transparent colorless variety of calcite … New Collegiate Dictionary
Iceland spar — calcite (calcium carbonate) … Eponyms, nicknames, and geographical games
