A choice old Carn Brea (Cornwall) specimen of Chalcopyrite crystals in Tetrahedral form, well coated with a dark Bornite. Excellent pedigree, previous collections include AK Borland, Brian Lloyd and John Marshall (labels etc included). The matrix is mostly Quartz with some pinkish crystals and some areas of Pyrite. The Chalcopyrites are quite sharp, up to 1.4 CM these are protected in two main vugs so most are in quite good condition. Some minor chipping is noted under loupe inspection, overall displays and looks clean. This mine has long ago vanished but over 100 years ago it produced some great Bornite and Chalcopyrite. A nice specimen from a significant locality in Cornwall.
Chalcopyrite on Calcite
Concepcion del Oro
9.7 x 7.4 x 6.4 CM (cabinet)
A large scalenohedral Calcite crystal is encrusted with Chalcopyrite crystals many of which are dusted with sparkling drusy Quartz. The Chalcopyrite is mostly coated with dark Bornite patina which makes a strong contrast as well. Aside from a few very small bruises the Chalcopyrite is in fine condition, has classic good form and overall is a very esthetic example from this famed locale. Ex Charles M Noll collection, I have never seen a better example from Concepcion del Oro, and this is a super esthetic Chalcopyrite from anyplace.
Great Chalcopyrite crystals are remarkably rare, these are superb, sharp and quite large. Set on a "melted" Galena matrix with scattered crystals of Sphalerite, the Chalcopyrites are perfect, no chips, cracks or any damage. These have a nice patina and dark brassy color that sets off the well defined striations. Textbook perfect forms these show both single crystals and twins in fine detail. We try to grab any great Chalcopyrite crystals from this region. I believe they are some of the best ever found when they are this well defined. In person this is especially impressive and it is one of the most esthetic we have seen. Individual crystals are just under 5 CM, and the contrast with the matrix is strong. This specimen is also a "floater" it is crystalized all around and displays fine from most any angle.
Chalcopyrite with Quartz
Yaogangxian Mine, Yizhang County, Chenzhou Pref.
4.3 x 3.8 x 3.1 CM (miniature)
We do not see many good Chalcopyrites from Yaogangxian, although it was a common mineral there. This is an excellent, complete cluster of fine sharp crystals in outstanding condition. Very well defined striations, good patina and esthetic composition, this is all in all a choice piece. For a quite common mineral good Chalcopyrites crystals of this size are rare.
From an older European collection, these are well formed, fine Chalcopyrites with some complex Galena all dusted with Calcites. The original label lists this as from Rodna, but it is unlike any other example we have seen from the locale, and unlike any of the better known Romanian localities (Cavnic, Turt etc). As often happens with old collections we can not always fully trust the locality information, but if correct this is especially fine for the locality and a significant older Roumanian piece with character. Undamaged. The Chalcopyrites reach 2.6 CM and are textbook sharp.
An outstanding cabinet display piece of fine, large (to 4.5 CM) crystals of iridescent Chalcopyrite on contrasting Sphalerite. Although Chalcopyrite is a common mineral, great crystals especially large ones are surprisingly rare. The patina and metallic color play make this especially attractive. An older Casapalca specimen in fine condition overall, with a few small chips mostly on outer edges. As Chalcopyrite is very brittle it is rare to have such large crystals in this fine condition.
A delicate and esthetic classic. The early French Creek Chalcos are distinctive and very much sought after, they are definitely the most desired US Chalcopyrites. The skeletal growth structures make very intricate geometric forms that are well presented here. The Enstatite crystals reach 1.6 CM and are all terminated. These make a fine contrast and the overall presentation is very fine.