Anhydrite
 | CaSO4CaSO₄
These samples of anhydrite are displayed in the Smithsonian Museum of Natural History. Anhydrite is a sulfate mineral of calcium with the composition CaSO4. The sample at left is about 5 cm across and is from Naica, Chihuahua, Mexico. 这些石膏样品陈列在史密森尼自然历史博物馆中。石膏是一种钙硫酸盐矿物，化学式为CaSO₄。左侧的样品直径约5厘米，来自墨西哥奇瓦瓦州的纳伊卡。
The name anhydrite, or "no water" alludes to the fact that there is no water in the structure, in contrast to gypsum, which is also calcium sulfate but incorporates water in its structure. “无水”这一名称暗示了其结构中不含水，与石膏不同，石膏虽也是硫酸钙，但其结构中包含水。
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This strange sample is decribed as quartz after anhydrite. This means that the sample is quartz which has taken the place of the anhydrite, but retains the geometry of the anhydrite. It is a large sample, some 40 to 50 cm across. It is from Danialo mine, Rio Grande do Sul, Brazil. 这种奇特的样本被描述为石英，取代了石膏。这意味着该样本是石英，它取代了石膏的位置，但保留了石膏的形态。这是一个较大的样本，直径约为40到50厘米。它来自巴西圣保罗州的丹ialo矿。
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 | "Quartz after anhydrite" means that it initially formed as anhydrite crystals and then was chemically replaced by quartz while retaining the crystal shape of the anhydrite precursor. ‘含石膏的石英’意味着它最初形成于石膏晶体，随后被石英化学置换，但保留了石膏前体的晶体形态。 This sample is about 20cm across and is from Irai, Rio Grande do Sul, Brazil. 这个样本宽约20厘米，来自巴西圣保罗州伊拉伊。 |
Mindat: Anhydrite
| Minerals
矿物 |
| HyperPhysics*****Geophysics
HyperPhysics ***** 地球物理学 | R Nave |