Rutile

Japanese: 金紅石 - きんこうせき（英語表記）rutile

Name of mineral ore. Also called rutile. It is in a homogeneous tetramorphic relationship with anatase, brookite, and an unnamed _TiO2 mineral, but the stability relationship between them is unclear. It occurs in quartz veins that penetrate igneous and metamorphic rocks, especially as needle-shaped crystals in transparent crystals of quartz, and in volcanic and pyroclastic rocks (pyroclastic rocks) where a large amount of aluminum minerals have been produced by hydrothermal alteration. It also occurs in granitic pegmatites, and sometimes contains large amounts of niobium (Nb) and tantalum (Ta). Its euhedral shape is a square column with a well-developed pyramidal surface. Famous production areas include Bizan, Tokushima City, Tokushima Prefecture, and Teshirogi, Koriyama City, Fukushima Prefecture. The name comes from the Latin word rutilus, meaning "red."

[Akira Kato]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

鉱石鉱物名。英名そのままでルチルともいう。鋭錐石(えいすいせき)、板チタン石および未命名のTiO₂鉱物と同質四像関係にあるが、これらの安定関係については明らかになっていない。火成岩や変成岩を貫く石英脈中、とくに水晶の透明な結晶中に針状結晶をなすほか、熱水変質を受けて多量のアルミニウム鉱物が生成された火山岩・火砕岩（火山砕屑(さいせつ)岩）中に産する。花崗(かこう)岩質ペグマタイト中にも産し、ときに多量のニオブNbやタンタルTaを含む。自形は錐面が発達した正方柱状。徳島県徳島市眉山(びざん)や福島県郡山市手代木(てしろぎ)などは有名な産地。命名は「赤」を意味するラテン語rutilusに由来する。

［加藤　昭］