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| a screen or mat covered with a dark material for shielding a camera lens from excess light or glare. |
| a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question. |
cohenite
an iron nickel carbide mineral [(Fe,Ni)3C] that occurs as an accessory constituent of iron meteorites, including all coarse octahedrites containing 7 percent nickel or less, and that is a rare constituent of some chondritic stony meteorites and micrometeorites. Another iron nickel carbide, haxonite [(Fe,Ni)23C6], also occurs in these meteorites. Cohenite closely resembles another meteoritic mineral, schreibersite, and it may be more common in meteorites than is supposed. When manufactured on Earth, as in steel, it is called cementite. For detailed physical properties, see native element (table)
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