FMF - Friends of Minerals Forum, discussion and message board

[jorge santos garcia]

Hello all

I've read that ettringite may dehidrate over time and became white, opaque and dull, sometimes it even may alter to gypsum. Is there any kind of special care to avoid that to happen?

Thanks

Jorge

[alfredo]

A bigger danger, I think, is reaction with CO2 gas from the atmosphere, forming a dull white film of Ca carbonate on the surface. You should keep it in a closed container, with a bit of slaked lime - Ca(OH)2 - for absorbing carbon dioxide. And don't breathe on it!

[jorge santos garcia]

Thank you Alfredo, I will hold my breath everytime I look at it.

Cheers

Jorge