asterismal, adj.
/as"teuh riz'euhm/, n.
1. Astron.
a. a group of stars.
b. a constellation.
2. Mineral. a property of some crystallized minerals of showing a starlike luminous figure in transmitted light or, in a cabochon-cut stone, by reflected light.
3. three asterisks printed to draw attention to a passage it precedes.
[1590-1600; < Gk asterism(ós) a marking with stars. See ASTERISK, -ISM]

* * *

      in mineralogy, starlike figure exhibited in light reflected or transmitted by some crystals. The stars shown by star sapphires, some phlogopite mica, rose quartz, and garnet are due to minute oriented crystals (often rutile) included within the mineral; several sets of inclusions are present, and each set produces its own ray. In minerals with hexagonal or pseudohexagonal symmetry (three equal axes at 120° all perpendicular to a fourth), three such rays produce a six-pointed star; and in those with isometric symmetry (three equal, mutually perpendicular axes), two rays produce a four-pointed star.

* * *

Universalium. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Asterism — may refer to:* Asterism (astronomy), a pattern of stars * Asterism (gemmology), an optical phenomenon in gemstones * Asterism (typography), a moderately rare typographical symbol denoting a break in passages …   Wikipedia

  • asterism — asterísm s. n. Trimis de siveco, 10.08.2004. Sursa: Dicţionar ortografic  ASTERÍSM s.n. 1. Proprietate a unor minerale de a prezenta în masa lor cercuri luminoase în lumina reflectată prin ele în diferite direcţii. 2. (Rar) Constelaţie. [< fr …   Dicționar Român

  • Asterism — As ter*ism, n. [Gr. ?, fr. asth r star; cf. F. ast[ e]risme.] 1. (Astron.) (a) A constellation. [Obs.] (b) A small cluster of stars. [1913 Webster] 2. (Printing) (a) An asterisk, or mark of reference. [R.] (b) Three asterisks placed in this… …   The Collaborative International Dictionary of English

  • asterism — 1590s, a constellation, a group of stars, from Gk. asterismos a marking with stars, from aster star (see ASTRO (Cf. astro )). Any grouping of stars, whether a constellation or not (though in modern use, usually the latter). The Big Dipper is an… …   Etymology dictionary

  • asterism — [as′təriz΄əm] n. [Gr asterismos, a marking with stars < asterizein, to mark with stars < astēr, STAR] 1. a group or cluster of stars that may or may not form a constellation 2. Mineralogy a starlike figure produced in some crystals by… …   English World dictionary

  • Asterism — ⁂ Satzzeichen Punkt ( . ) Komma ( , ) Semikolon ( ; ) Doppelpunkt ( : ) …   Deutsch Wikipedia

  • Asterism (astronomy) — In astronomy, an asterism is a pattern of stars seen in Earth s sky which is not an official constellation. Like constellations, they are composed of stars which, while they are in the same general direction, are not physically related, often… …   Wikipedia

  • Asterism (gemmology) — This article is about the characteristic in some gems. For other uses, see Asterism (disambiguation). Asterism on the surface of a blue star sapphire. This is the 182 carat (36.4 g) Star of Bombay, housed in the National Museum of Natural History …   Wikipedia

  • Asterism (typography) — For other uses of this term, please refer to Asterism disambiguation page. In typography, an asterism is a rarely used symbol consisting of three asterisks placed in a triangle (Unicode|⁂). It is used to call attention to a passage or to separate …   Wikipedia

  • asterism — noun Etymology: Greek asterismos, from asterizein to arrange in constellations, from aster , astēr Date: 1598 1. a. constellation b. a small group of stars 2. a star shaped figure exhibited by some crystals by reflected light (as in a star… …   New Collegiate Dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”