These rock crystals are made from a mineral called gypsum and they are over a meter long.

岩石晶体由一种叫做石膏的矿物构成，长度过一米。

And then those are an ancestor of Liezenstein and reading stones, which I think were often made of something like rock crystal.

然后是利森斯坦和读石的祖先，它们通常是由类似岩石水晶的材料制成的。