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Cube forms, octahedron and dodecahedron.
Group of pentadodecahedral pyrite crystals on a matrix with small quartz and tennantite crystals. Pyrite shows striated faces and an exceptional luster. In some of the pentadodecahedral pyrite crystals, we can observe edges truncated by the cube faces and some vertices by the octahedron.
This remarkable specimen shows a matrix formed by tabular barite crystals, partially covered with aggregates of tetrahedrite-(Zn) crystals, rich in Ag. With well-defined faces and edges, forming globular aggregates on the barite. A rarity.
Numerous rhodochrosite crystals are disposed on a druse of quartz crystals, defined, transparent to translucent. They present a very remarkable richness of faces, to be enjoyed under magnification, highlighting numerous reflection twins, with dull faces and bright faces alternating by geometry. A very aesthetic curiosity.
A large group of rhodochrosite crystals, with pointed scalenohedron shapes but with striated faces and a very aesthetic pearly luster. The pink-red colour is more intense inside the crystals. It seems that a second generation of rhodochrosite has covered the primary crystals. It is accompanied by crystals of hyaline quartz, together with colourless, well-defined fluorite cubes with opaline faces, except at the vertices, a curious geometry. Aesthetic piece.
Group of rhombohedral calcite crystals of very good size, with defined faces and edges, with interpenetration twins. Slightly pinkish white in colour, matt faces. This specimen stands out for its intense fluorescence and more than notable fluorescence when illuminated with UV-LW light. It comes from the Jaime Murria collection (Barcelona).
Group of geocronite-jordanite crystals, with striated pseudohexagonal shapes, very bright and rich in facets. The matrix is mainly composed of geocronite-jordanite, with various cavities where we observe striated crystalline faces.The analyzes show a correlation between geocronite-jordanite, both are isostructural and form series. Crystals analyzed show that the composition moves in the intermediate zone of the series. The geocronite-jordanite crystals are accompanied by sphalerite, galena, associated with transparent crystals of green fluorite.
Old specimen of rhodonite from this Peruvian mine. Formed by parallel growths of tabular crystals, with a soft pink color and shine. With pyrite in matrix.
Group of rhodochrosite crystals included in the matrix. Bright and transparent. From this classic Peruvian mine.
Parallel growth of hübnerite crystals, of very good size, with evident reddish reflections. With defined terminal faces, translucent on edges and with brilliance. With hyaline quartz crystals. Excellent old piece from this Peruvian mine.
Scalenohedral rhodo crystals with a whitish patina. They are accompanied by very brilliant hyaline quartz crystals.
Group of geocronite-jordanite crystals, with striated pseudohexagonal shapes. They have a lighter gray sheen than the galena with which they are often associated. The analyzes show a correlation between geocronite-jordanite, both are isostructural and form series. The crystals analyzed (both these that we present and others) show that the composition moves in the intermediate zone of the series. Therefore, the correct thing would be to label these specimens as geocronite-jordanite, avoiding saying that they are only geochronite. We will send all analyzes to the buyer.
The geocronite-jordanite crystals are accompanied by crystals of sphalerite, of galena, associated with transparent crystals of green fluorite, both cubo-octahedral, the latter truncated by the faces of the cube and the trapezohedron.
Group of geocronite-jordanite crystals, with striated pseudohexagonal forms. They have a lighter gray luster than the galena with which they are often associated. The analyzes show a correlation between geochronite-jordanite, both are isostructural and form series. The crystals analyzed (both these that we present and others) show that the composition is in the intermediate zone of the series. Therefore, the correct way is to label these specimens as geocronite-jordanite, avoiding saying that they are only geochronite. We will send all analytical reports to the buyer.
The geocronite-jordanite crystals are found on a matrix formed by complex sphalerite crystals, almost black in color, associated with transparent green fluorite crystals, octahedral cubes, truncated by the cube and trapezohedron faces.
Group of interpenetrated pyrite crystals with an exceptional luster. This specimen stands out for its complex crystallography, with cube shapes, triglyphic striations, and vertices rich in probably trapezohedral faces. A piece to enjoy in its study, the kind that I like...
Group of cube octahedral pyrite crystals forming a very aesthetic and brilliant aggregate.
Group of pyrite crystals that show well defined faces of the cube and the octahedron. Very well defined faces and edges, showing triglyphic striations on the faces of the cube and not on the octahedron, as is to be expected. With an exceptional luster. It is accompanied by quartz crystals.
Group of pyrite crystals with cube and dodecahedron faces, with diploid forms, striated faces, certainly complex crystallography, which adds interest to the specimen. Crystals are interpenetrated. The brightness is exceptional, difficult to photograph. It is accompanied by quartz crystals.
This specimen was purchased at the Expominer fair (Barcelona) in 1985 from a dealer who brought Peruvian material. It was labeled as "enargite" from Huancavelica, a Peruvian mining region well known among mineral collectors. The specimen shows numerous crystals with a metallic luster, isolated or in groups, on a sulfide matrix (mainly pyrite). By observing them carefully and using a magnifying glass, we were able to see different crystalline forms that indicated the presence of various species. We proceeded to extract some crystals to study them.
SEM-EDS analysis indicated that elongated prismatic crystals with polysynthetic growths on the faces and hopper shapes (perimorphosis?) were a copper sulfoantimonide, with some bismuth and arsenic. This composition and its percentages correspond to chalcostibite, and the Bi would indicate the series with emplectite. Chalcostibite was confirmed by X-ray diffraction (XRD). An unusual species and less so for this Peruvian mine.
Other crystals showed prisms with faces striated and truncated by the pinacoid. Their analysis indicated that it was a copper-lead sulfoantimonide, with traces of Bi, consistent with twinned bournonite, a species also confirmed by XRD.
On the matrix we observe crystals with tetrahedron shapes, sometimes flattened. XRD indicated the presence of tetrahedrite. SEM-EDS analysis of small crystals associated with chalcostibite indicated that it could be tetrahedrite-(Zn), with possible argentotetrahedrite-(Zn). We will send labels and all the analysis reports to the buyer.
Rich group of quartz crystals, translucent to hyaline, and with the terminal faces of the rhombohedron different from the usual ones. Among them, a very good size doubly terminated crystal stands out, well defined and with the faces of the prism with striations perpendicular to the main axis. They are disposed on a matrix with quartz and sphalerite crystals.
These specimens of Peruvian arsenopyrite stand out for their excellent luster and perfection of its crystals. With the camera I am not able to capture its real beauty. On a sulfide matrix we can enjoy hundreds of arsenopyrite crystals, prismatic, with defined terminal faces, rather than well-defined. They're accompanied by chalcopyrite crystals with dull luster, but gold tone, also well-defined and twinned. Brilliance and quality. Good sized specimen.
These specimens of Peruvian arsenopyrite stand out for their excellent luster and perfection of its crystals. With the camera I am not able to capture its real beauty. On a sulfide matrix we can enjoy hundreds of arsenopyrite crystals, prismatic, with defined terminal faces, rather than well-defined. They're accompanied by chalcopyrite crystals with luster and gold color, also well-defined and twinned. Brilliance and quality.
Very esthetic miniature formed by a group of quartz crystals covered by beveled cubic pyrite on which various tabular crystals of hübnerite stand out, well defined and with a very visible red transparence. Specimen from the Joan Astor collection, acquired in 1982 from Bailey Minerals (Ángel Jesús Talabán García, Segovia 1942-Madrid 2007).
Druse of pyrite crystals with faces of the cube and rhobododecahedron, striated faces, complex crystallography, which adds interest to the specimen. Back side is curiously flat. The luster is exceptional, not easy to take photos. The crystals are interpenetrated. A classic from the mine from which the bases for the FIFA football award "Ballon d'Or" are obtained...
Group of chalcopyrite crystals, bright, interpenetrated, with well defined edges. On the faces of the crystals we can see small aggregates of crystals, probably tetrahedrite. They are accompanied by sphalerite crystals on matrix. An old piece, from the time of those that are preserved in the Freiberg Mining School Museum.
Group of cyclically twinned bournonite crystals, with a metallic gray color, interpenetrating each other. They are disposed on a matrix of very brilliant octahedral pyrite, partially covered by complex sphalerite crystals.