hardness


hardness
/hahrd"nis/, n.
1. the state or quality of being hard: the hardness of ice.
2. a relative degree or extent of this quality: wood of a desirable hardness.
3. that quality in water that is imparted by the presence of dissolved salts, esp. calcium sulfate or bicarbonate.
4. unfeelingness or jadedness; callousness.
5. harshness or austerity, as of a difficult existence.
6. South Midland U.S. ill will; bad feelings: There's a lot of hardness between those two boys.
7. Mineral. the comparative ability of a substance to scratch or be scratched by another. Cf. Mohs scale.
8. Metall. the measured resistance of a metal to indention, abrasion, deformation, or machining.
[bef. 900; ME hardnes, OE heardnes. See HARD, -NESS]

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Resistance of a mineral to scratching, described relative to a standard scale of 10 minerals known as the Mohs hardness scale.

Hardness is an important diagnostic property in mineral identification. There is a general link between hardness and chemical composition (via crystal structure); thus, most hydrous minerals, halides, carbonates, sulfates, and phosphates are relatively soft; most sulfides are relatively soft (two exceptions being marcasite and pyrite); and most anhydrous oxides and silicates are hard. See also hardening.

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Universalium. 2010.

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  • Hardness — Hard ness, n. [AS. heardness.] 1. The quality or state of being hard, literally or figuratively. [1913 Webster] The habit of authority also had given his manners some peremptory hardness. Sir W. Scott. [1913 Webster] 2. (Min.) The cohesion of the …   The Collaborative International Dictionary of English

  • Hardness — Hardness. См. Твердость. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов

  • hardness — index brutality, congealment Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • hardness — (n.) O.E. heardnysse; see HARD (Cf. hard) + NESS (Cf. ness). Meaning difficulty of action or accomplishment is late 14c …   Etymology dictionary

  • hardness — [härd′nis] n. 1. the state or quality of being hard (in various senses) 2. the relative capacity of a substance for scratching another or for being scratched or indented by another …   English World dictionary

  • Hardness — This article is about mechanical properties of materials. For other uses, see Hard. Hardness is the measure of how resistant solid matter is to various kinds of permanent shape change when a force is applied. Macroscopic hardness is generally… …   Wikipedia

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  • hardness —    a measure of the hardness of a metal or mineral. Hardness is a property easy to appreciate but difficult to quantify and measure.    The Mohs hardness scale is used in geology to give a rough estimate of hardness by testing which minerals are… …   Dictionary of units of measurement

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