[[Crystals]] are usually [[flattened]], with sharp edges and sharp, thin cross section; no [[right angles]] on faces or edges; all forms are [[pinacoids]] (open forms made up of two [[parallel]] faces). Chesterman, pp. 33-34 | [[Crystals]] are usually [[flattened]], with sharp edges and sharp, thin cross section; no [[right angles]] on faces or edges; all forms are [[pinacoids]] (open forms made up of two [[parallel]] faces). Chesterman, pp. 33-34 |