Hi,
Just to let you know that the Chalcathites being sold for ridiculous sums of money are NOT the "real deal" - if you Google 'Chalcanthite', you will see that it is a rare copper sulphate-based mineral that is found in dry, arid regions and is usually a crust, occasionally a blade - what these Polish ripoff merchants are selling is chemical grade copper sulphate, dissolved in a bathtub and grown much in the way we would grow crystals in a jar when we were kids.
This is what real Chalcanthite looks like:

They are not "Chalcathite crystals" they are copper sulphate crystals - one is a mineral, the other is simply a lab chemical.  The chemical composition may be the same, but the method of production isn't!  Real Chalcathite is rare in nature due to it's solubility (hence the need for arid conditions) - this gear they are selling will slowly become anhydrous, turn pale blue and start to crumble if you keep it in a dryish environment like a lounge. What a waste of $$$$$!!

Why do you think that the bidders' names are kept private? So you cannot advise them that they are buying a fake, sold as the real thing.

DO NOT BUY IT - HELP EBAY TO KILL OFF THE FRAUDS AND FAKERS AND MAKE EBAY A BETTER PLACE TO BUY FROM.