{"product_id":"tetrahedrite-with-chalcopyrite-and-galena-1","title":"TETRAHEDRITE with CHALCOPYRITE and GALENA","description":"A quite magnificent specimen of 'Tetrahedrite' with Chalcopyrite and Galena from Herodsfoot mine at Lanreath, Cornwall. This large cabinet specimen has a matrix base of massive milky white Quartz veinstone whose top surface is covered with thick tabular pseudomorphs of Quartz after Baryte. These are overgrown by well-developed crystals of dark grey 'Tetrahedrite' many of which have a fine surface coating of golden brassy Chalcopyrite.  Partly coating and surrounding these are dozens of equant dark grey Galena crystals which form as modified cubo-octahedrons. This material was discovered at Herodsfoot mine at the same time as the famous cog-wheel Bournonite crystals (c. 1858). 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. There is damage in several places, but also many beautiful intact Chalcopyrite-coated Tetrahedrite crystals and Galena too. A fine and very large example which displays many of the mineralogical characteristics Herodsfoot mine is rightly famous for. Ex Glyn Cunnick collection with label.","brand":"Crystal Classics","offers":[{"title":"Default Title","offer_id":46543059353775,"sku":"CC13554","price":1500.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0710\/8516\/2671\/files\/CC13554.png?v=1770305703","url":"https:\/\/crystalclassics.com\/products\/tetrahedrite-with-chalcopyrite-and-galena-1","provider":"Crystal Classics","version":"1.0","type":"link"}