“Lime #olivine” (which I guess is a calcium analogue of forsterite) “does not hydrate, and is avoided in #cement manufacture”, but apparently heating it above 500° “cures” that “problem”. Also called #larnite. Also, this page explains that forsterite weathers to serpentine and brucite in nature.
on 02015-08-30"Larnite" is calcium silicate, so I guess that’s what you get if you precipitate #waterglass with calcium salts. It’s Mohs hardness 6, a lot harder than talc. Occurring as a phase in concrete, it’s called “belite”. “readily prepared from reactive CaO and SiO₂ at 300 °C.” #minerals
on 02015-08-30