brown tourmaline

Mira otros diccionarios:

• Tourmaline — Schorl Tourmaline General Category Cyclosilicate Chemical formula (Ca,K,Na,[ …   Wikipedia

• Tourmaline — Tour ma*line, n. [F. tourmaline, cf. It. turmalina, tormalina, NL. turmalina, turmalinus; all fr. tournamal, a name given to this stone in Ceylon.] (Min.) A mineral occurring usually in three sided or six sided prisms terminated by rhombohedral… …   The Collaborative International Dictionary of English

• tourmaline — tourmalinic /toor meuh lin ik/, adj. /toor meuh lin, leen /, n. any of a group of silicate minerals of complex composition, containing boron, aluminum, etc., usually black but having various colored, transparent varieties used as gems. Also,… …   Universalium

• turmaline — Tourmaline Tour ma*line, n. [F. tourmaline, cf. It. turmalina, tormalina, NL. turmalina, turmalinus; all fr. tournamal, a name given to this stone in Ceylon.] (Min.) A mineral occurring usually in three sided or six sided prisms terminated by… …   The Collaborative International Dictionary of English

• Hornfels — (German, meaning hornstone ) is the group designation for a series of contact metamorphic rocks that have been baked and indurated by the heat of intrusive igneous masses and have been rendered massive, hard, splintery, and in some cases… …   Wikipedia

• Paraíba — Infobox Brazilian State name = State of Paraíba motto = anthem = capital = João Pessoa latd= |latm= |latNS= |longd= |longm= |longEW= largest city = João Pessoa demonym = Paraibano leader name1 = Cássio Cunha Lima leader name2 = José Lacerda Neto… …   Wikipedia

• Silicate minerals — ▪ Table Silicate minerals name colour lustre Mohs hardness specific gravity Tectosilicates (three dimensional networks) feldspar (for other examples, see feldspar) orthoclase flesh red, white to pale yellow, red, green vitreous 6–6½ 2.6… …   Universalium

• Pegmatite — is a very coarse grained igneous rock that has a grain size of 20 mm or more; such rocks are referred to as pegmatitic .Most pegmatites are composed of quartz, feldspar and mica; in essence a granite . Rarer intermediate and mafic pegmatite… …   Wikipedia

• Optical mineralogy — A petrographic microscope, which is an optical microscope fitted with cross polarizing lenses, a conoscopic lens, and compensators (plates of anisotropic materials; gypsum plates and quartz wedges are common), for crystallographic analysis.… …   Wikipedia

• dravite — /drah vuyt/, n. a brown variety of magnesium tourmaline. [ < G Dravit. See DRAVA, ITE1] * * *       a brown, magnesium rich variety of tourmaline. See tourmaline. * * * …   Universalium

• Important gemstones — ▪ Table Important gemstones mineral gem name colour Mohs hardness* specific gravity* beryl aquamarine sky blue to greenish blue 7½–8 2.68–2.71 emerald green 2.68–2.74 goshenite colourless; greenish yellow, yellow green, brownish same as… …   Universalium