2 Months of Patience
Posted by aonomus on August 7, 2010
Some things can be done in a hurry, some things can’t. While these aren’t as good as I’d have liked, they are still something to appreciate. Copper sulfate, CuSO4, over exactly 2 months now in fact.
Above: 2 different CuSO4 crystals from different angles, scale in mm.
Below: a smaller/medium crystal, and seed crystals for the next batch.
Procrastinatus 
Christopher Olah said
Pretty!
The only copper sulfates in my mineral book have hydroxyl groups on them — Bronchantite (Cu4(SO4)(OH)6) and Antlerite (Cu3(SO4)(OH)4). They have a similar crystal structure to your crystals but a deep green colouration (I’m guessing it’s the oxidised copper)… They’re translucent like yours as well.
aonomus said
Minerals tend to be weird because of non-stoichiometric ratios of anions and cations, with the difference typically being made up by oxides/hydroxides.