Wollastonite (English spelling)

Japanese: ケイ灰石(珪灰石) - けいかいせき（英語表記）wollastonite

A triclinic mineral belonging to the pyroxene family with a chain structure of chemical composition CaSiO _3. It has a specific gravity of 2.92, Mohs hardness of 4.5-5, a melting point of 1512°C, and is a mass of white fibrous or fine-grained crystals. Cleavage is prominent in {100}, but also in {001} and {02}. There are several other polymorphic structures, including the monoclinic parawollastonite. At temperatures above 1150°C, it transforms into pseudowollastonite, which has a homogeneous heterocrystalline three-membered ring (SiO ₃ ) ₃ structure.

Source: Heibonsha World Encyclopedia, 2nd Edition Information

Japanese:

化学成分CaSiO₃の鎖状構造をもつ準輝石に属する三斜晶系の鉱物。比重2.92，モース硬度4.5～5，融点1512℃，白色繊維状あるいは細粒結晶の集合塊。へき開は｛100｝に顕著，｛001｝や｛02｝にも強い。ほかに単斜晶系のパラケイ灰石parawollastoniteをはじめいくつかの多型構造がある。1150℃以上では同質異晶の3員環(SiO₃)₃構造をもつ偽ケイ灰石pseudowollastoniteに転移する。

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