Saying they go for $4000 or asking $4000 is not the same as going for $4000. A quick google turns up plenty of malachite chessboards for much less:
http://www.africancraftsmarket.com/Chessboardmalachite_details.htm
http://www.liveauctioneers.com/item/14623822_vintage-italian-malachite-and-marble-chess-board
http://www.ebay.co.uk/itm/STUNNING-VINTAGE-MALACHITE-STONE-CHESS-BOARD-/191147374192#ht_4755wt_798
Personally, I wouldn't pay even $10 for one. This kind of board does nothing for me.
Have you guys seen this rare chess board? I found it here http://www.ebay.com/itm/161297409050 today. Well, ususally they go for 4,000.00 but this ones under 1k. Can anyone loan me the money?