We present the crystal structure, composition, and occurrence of stöfflerite, the naturally occurring Ca-aluminosilicate with hollandite-type structure. Stöfflerite is a high-pressure polymorph of anorthite and an approved mineral. The type material was found in the shergottitic martian meteorite Northwest Africa 856. Type stöfflerite (Sto60Lin40) assumes space group I4/m with unit-cell dimensions a = 9.255(1) Å, c = 2.742(3) Å, V = 235.1(2) Å3, and Z = 2.

中文翻译：

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钙铁矿结构中的辉锰矿，（Ca，Na）（Si，Al）4O8：火星陨石NWA 856中钙长石的一种新型高压多晶型物

我们介绍了辉锰矿的晶体结构，组成和发生情况。辉锰矿是天然存在的具有钙锌矿型结构的钙铝硅酸盐。辉缕石是钙长石和经批准的矿物的高压多晶型物。这种类型的材料是在陨石质的火星陨石西北非洲856中发现的。类型为Stöfflerite（Sto60Lin40）的空间群为I4 / m，单位像元尺寸为a = 9.255（1）Å，c = 2.742（3）Å，V = 235.1（ 2）Å3，Z = 2。