Description: TETRAHEDRITE * fine crystals of tetrahedrite (largest size 12mm) on light-ping manganoan calcite ** small fine crystals of pyrite ** super specimen from famous locality * size: 80 X 60 X 37mm weight: 208g origin: Boldut Mine, Cavnic, Maramureș Co., Romania Tetrahedrite forms a solid solution series with the rather rare mineral tennantite (Cu12As4S13, Copper Arsenic Sulfide). The two share the same crystal structure but they differ in the percentage of arsenic versus antimony. Antimony rich specimens are tetrahedrite while arsenic rich specimens are tennantite. Some iron, zinc and/or silver always substitute for the copper in both minerals up to approximately 15 % .Tetrahedrite is named for its common crystal form, the tetrahedron. The tetrahedron is an interesting isometric crystal form. It is obvious where the four three fold axes of the isometric system belong, as each one exits out of the crystal through each of the four identical "pyramidal" peaks. However the four fold axes are evidently missing. They aren't, they are just four fold rotoinversion axes. A four fold rotoinversion axis takes a face, rotates it 90 degrees (one fourth of a rotation) and then inverts it (up to down & right to left) through the crystal to the other side. Then it rotates it again 90 degrees and inverts it again through the crystal. Another rotoinversion operation and finally another (four in all) and the face is back, exactly where it started. The result is two faces on the "top" and two on the "bottom" of the crystal but in perpendicular orientation. The tetrahedral faces are in many instances modified by other crystal forms giving the crystals multiple facets while still retaining the basic tetrahedral shape.Tetrahedrite can form interesting and handsome mineral specimens. Often it will contain a certain percentage of silver and be used as a minor ore. The multi-faceted tetrahedral crystals as well as the flat faced simple tetrahedral crystals can be very striking and a real pleasure for mineral collectors to own. PRIORITY AIR MAIL SHIPPING TO WORLDWIDE 7-14 business days to deliver Shipping charges in accordance to weightIf you have multiwins, please email to request a combined shipping total to save you on shipping costs.
Price: 250 USD
Location: Ceske Budejovice
End Time: 2023-12-18T02:13:57.000Z
Shipping Cost: 0 USD
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Restocking Fee: No
Return shipping will be paid by: Buyer
All returns accepted: Returns Accepted
Item must be returned within: 14 Days
Refund will be given as: Money Back
