rare bimetallic silver / tantalum coin

[Benas 0]

For sale rare bimetallic silver / tantalum coin from Kazakhstan:

Kazakhstan 500 Tenge "1st space setallite of Earth" 2007 proof

BIMETALLIC: inner disk is made of Tantalum, external ring is made of Silver.

Total weight 41,4 gr. Fineness: 925 Silver, 14,6 gr. / Tantalum 38,61 gr.

Mintage 4000 pcs only !!!!!!!!!

PRICE ............ 140.00 USD

Other dealers and collectors sell this coin more expensiv.

Please compare: http://global.ebay.com/gbh/viItem?ItemId=130212103277

Tantalum is a chemical element with the symbol Ta and atomic number 73. A rare, hard, blue-grey, lustrous, transition metal, tantalum is highly corrosion-resistant and occurs naturally in the mineral tantalite, always together with the chemical similar niobium. The chemical inertnes of tantalum made it a valuble substance for laboratory equipment and substitute for platinum, but its main use today is in tantalum capacitors.

If you interested in this coin please let me know.