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.

然是利森斯坦和读石祖先，我认为它们通常是由类似岩石水晶材料制成。