{"product_id":"tetrahedrite-with-chalcopyrite","title":"TETRAHEDRITE   with CHALCOPYRITE","description":"Golden, Chalcopyrite-coated 'Tetrahedrite' crystals are an absolute Cornish classic. Discovered at Herodsfoot mine at the same time as the famous cog-wheel Bournonite crystals (c. 1850s), these distinctive crystals are not quite unique from this mine, but are extremely rare from anywhere else, showing how specific the formation conditions were within the vein system. We should note here that due to the restructuring and renaming of the Tetrahedrite Group of minerals by the IMA in 2023, the Herodsfoot mine crystals should technically be labelled as \"Tetrahedrite Subgroup\" until detailed analytical data on these crystals is studied, but all collectors know them as Tetrahedrite and so we are sticking with that one here. This specimen is slightly different to others from this mine in that it displays matrix - the host rock - and the Tetrahedrite crystals are spaced out upon a thin veinlet of Milky Quartz which really makes them stand out. Associated with the Chalcopyrite-coated Tetrahedrite are small cubo-octahedral Galena crystals. The Tetrahedrite crystals, which reach up to 1.1 cm across, are classically tetrahedral in form, but with modified flattened tops and rounded edges with Chalcopyrite occurring as a very thin, almost iridescent, layer. A couple of the Tetrahedrite crystals towards one edge of the specimen are damaged, and reveal the darker grey internal Tetrahedrite, but most are in perfect condition including a twinned crystal right in the centre. A superb, old-time Cornish 'Tetrahedrite' and with pedigree - coming with old collection labels from Lindsay and Patricia Greenbank, the Scalisi collection and a prominent modern German collection.","brand":"Crystal Classics","offers":[{"title":"Default Title","offer_id":46545417404591,"sku":"CC28391","price":5000.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/8516\/2671\/files\/CC28391.png?v=1770390017","url":"https:\/\/crystalclassics.com\/products\/tetrahedrite-with-chalcopyrite","provider":"Crystal Classics","version":"1.0","type":"link"}