Rosell Minerales

Group of well defined microcline crystals partially covered by minor muscovite and white albite crystal growths. Accompanied by smoky quartz crystals with a uniform smoky tone and transparence.

Size: 10,1 x 6,3 x 4,5 cm.
Main crystal: 1,8 x 1,6 cm.
Found in 2000

Group of doubly terminated crystals of pseudomorphic hematite after magnetite, elongated and with defined faces and edges. They show exceptional skeletal growths, very marked and partially coated by recrystallizations of small crystals of lenticular hematite. The crystals were formed in the fumaroles of this enormous Argentinian volcano. The Payún Matrú is a large volcano with an intermediate morphological type between a volcanic shield and a stratovolcano, that is located 530 km from the oceanic fosa and marks the subduction zone of the Nazca plate. Currently this area is a national park and collecting minerals is prohibited.

 

Size: 8.5 x 5.0 x 4.3 cm.
Found in 2008

Group of cassiterite crystals, very sharp, with defined faces and edges, good brilliance and transparence showing toasted honey lights. They show very clear cyclic twins. They are disposed very aerial and aesthetically contrasting on a matrix of quartz crystals with arsenopyrite. From a classic locality.

Size: 7.0 x 5.3 x 4.0 cm.
Main crystal: 18 x 15 mm.
Found in 2016

Group of cassiterite crystals, very sharp, with defined faces and edges, good brilliance and transparence showing toasted honey lights. They show very clear cyclic twins. They are disposed very aesthetically contrasting on a matrix of quartz crystals. From a classic locality.

Size: 6.5 x 5.3 x 3.0 cm.
Main crystal: 14 x 12 mm.
Found in 2016

Group of cassiterite crystals, very sharp, with defined faces and edges, good brilliance and transparence showing toasted honey lights. They show very clear cyclic twins. They are disposed very aesthetically contrasting on a matrix of quartz crystals with arsenopyrite. From a classic locality.

Size: 4.8 x 4.5 x 3.5 cm.
Main crystal: 15 x 15 mm.
Found in 2016

These specimens of Bolivian galena are unusual in collections. These mines on Cerro Sayari (4,300 meters elevation) were mined for silver during the colonial times. In this sample we would like to emphisize a group of sharp galena crystals, with metallic luster and polysynthetic growths, showing cube faces and minor facets of the octahedron. Aesthetic piece and very rare on the market.

Size: 8.4 x 6.4 x 4.7 cm.
Main crystal: 21 x 20 mm.
Found in 2015.

These rounded nuggests are found nowadays in the bed of the river Viloque. They have been teared off from the mineralized veins by the glacial erosion and actually are found in gold placers. This piece is a classic example of these nuggets, intense silvery metallic luster, rounded by abrasion, and a good size for this locality. Native bismuth is known from many localities worldwide, but nuggets from Viloque River are the mostn known for the species.

 

Size: 1,9 x 1,4 x 1,3 cm. (10 g.)

A very aesthetic copper specimen formed by laminar to arborescent forms, with rounded crystals and very aerial disposed. The color is natural, withouth chemical treatments, and it shows some luster. It comes from Bolivian mine, near CoroCoro, famous for pseudomorphs of native copper after hexagonal cyclic twins of aragonite, but these laminar shape is uncommon for locality.

Size: 6,5 x 5,1 x 4,4 cm.
Found in 2012.

A huge size group of interpenetrated crystals of hexagonal shape, with a dark gray metallic color and brilliant luster. Crystals of this specimen remind wurtzite for its complex hexagonal shape and dipyramids observed. Many similar samples from this mine has been classified as wurtzite. For this reason we heve proceeded to analyze them. The results indicate that this is a really amazing and interesting pseudomorphosis of sphalerite after wurtzite. A great opportunity for psedomorph and Bolivian mineral collectors.

Studies were carried on by X-ray diffraction of the matrix and hexagonal crystals. They have shown that it is sphalerite. Also, the Raman spectra shows that in the innermost areas of the crystals wurtzite presence has been detected, the rest is sphalerite. SEM-EDS yield a composition:  (Zn1.05,Fe0.09)Σ=1.14S1.00.

Specimens of well developed wurtzite are unusual. This hexagonal zinc sulphide, with some iron, presents dimorphism with sphalerite. It is known that wurtzite is stable at high temperatures, low temperatures being the most stable phase sphalerite. This Bolivian mine is the type locality for the wurtzite. We will send the analysis reports to the specimen buyer.

Size: 9.6 x 8.9 x 4.8 cm.
Main crystal: 28 x 25 mm.

Analyzed specimen with report

A huge size group of interpenetrated crystals of hexagonal shape, with a dark gray metallic color and brilliant luster. Crystals of this specimen remind wurtzite for its complex hexagonal shape and dipyramids observed. Many similar samples from this mine has been classified as wurtzite. For this reason we heve proceeded to analyze them. The results indicate that this is a really amazing and interesting pseudomorphosis of sphalerite after wurtzite. A great opportunity for psedomorph and Bolivian mineral collectors.
Studies were carried on by X-ray diffraction of the matrix and hexagonal crystals. They have shown that it is sphalerite. Also, the Raman spectra shows that in the innermost areas of the crystals wurtzite presence has been detected, the rest is sphalerite. SEM-EDS yield a composition:  (Zn1.05,Fe0.09)Σ=1.14S1.00.
Specimens of well developed wurtzite are unusual. This hexagonal zinc sulphide, with some iron, presents dimorphism with sphalerite. It is known that wurtzite is stable at high temperatures, low temperatures being the most stable phase sphalerite. This Bolivian mine is the type locality for the wurtzite. We will send the analysis reports to the specimen buyer.

Size: 5.7 x 4.2 x 3 cm.
Main crystal: 15 mm.

Analyzed specimen with report

Group of interpenetrated crystals of hexagonal shape, with a dark gray metallic color and brilliant luster. Crystals of this specimen remind wurtzite for its hexagonal shape and dipyramids observed. Many similar samples from this mine has been classified as wurtzite. For this reason we heve proceeded to analyze them. The results indicate that this is a really amazing and interesting pseudomorphosis of sphalerite after wurtzite. Accompanied by nice brilliant franckeite globular crystal aggregates and small hexagonal prism of plumbogummite (also a pseudomorph). A great opportunity for psedomorph and Bolivian mineral collectors.

Studies were carried on by X-ray diffraction of the matrix and hexagonal crystals. They have shown that it is sphalerite. Also, the Raman spectra shows that in the innermost areas of the crystals wurtzite presence has been detected, the rest is sphalerite. SEM-EDS yield a composition:  (Zn1.05,Fe0.09)Σ=1.14S1.00.

Specimens of well developed wurtzite are unusual. This hexagonal zinc sulphide, with some iron, presents dimorphism with sphalerite. It is known that wurtzite is stable at high temperatures, low temperatures being the most stable phase sphalerite. This Bolivian mine is the type locality for the wurtzite. We will send the analysis reports to the specimen buyer.

Size: 7.3 x 5.2 x 3.6 cm.
Main crystal: 18 x 16 mm.

Analyzed specimen with report

A very rich specimen of this rare sulphosalt showing brilliant and sharp franckeite lanceolate crystals forming globular aggregates. They are accompanied by delicate and shiny needles of jamesonite and idiomorphic crystals stannite with a brown color and dull. This combination makes these samples pieces very interesting for systematic mineral collectors. We have analized each species and we will send analysis to the buyer.

Specimens from this mine are hard to distinguish from those of the neighboring San Jose mine and, since the administrative office for both mines was at San Jose, most Itos mine specimens in foreign collections ended up labelled "San Jose mine".

Size: 5,0 x 4,5 x 3.0 cm.
Main crystal: 4 x 3 mm. stannite

Mineral analizado / Analyzed species.

Rich group of octahedral magnetite crystals with a good size. Brilliant, intense gray metallic tone and disposed very aesthetically on the rocky matrix. A classic that is hard to see on the market.

Size: 12.0 x 10.4 x 4.5 cm.
Main crystal: 13 x 12 mm.
Found in 2002.

Ex-col. Joan Rosell.
Magnetic properties: It is attracted by magnets

Rich group of octahedral magnetite crystals with a good size. Brilliant, intense gray metallic tone and disposed very aesthetically on the rocky matrix. With a small ding. A classic that is hard to see on the market.

Size: 9.7 x 4 x 3.2 cm.
Main crystal: 12 x 12 mm.

Perfection! A nice crystal of vivianite, with a deep green color and well defined. With transparence that show the green tone characteristic for the species. Very aerial disposed on a solid sandstone matrix, sulfur free which ensures the stability of the specimen in the future. It is better in live than on the photo, but enjoy them. An exceptional specimen.

Size: 6,9 x 6,5 x 4,5 cm.
Main crystal: 38 x 20 mm.

Precio reducido-Reduced price 310€

Specimen of a little-known locality. These sample shows aggregates of silver crystals, with an intense luster and tones between white and golden. They are disposed on a matrix with quartz and iron oxides with which they contrast.

Size: 6.4 x 4.8 x 2 cm.
Main crystal: 8 mm.
Found in 08/2011

The Siglo XX mine is one of the most impressive Bolivian mining localities. It produces some amazing specimens of common species like quartz, few of the with the Japan-Law twin which are are well known in the mineral world. In this sample we can enjoy a good sized Japan-twin quartz crystals, with transparence and luster. This nice twin is disposed on a druse of hyaline quartz crystals.
To give a unique touch to the specimen a group of cassiterite crystals with good brilliance and deep black color, very rich in faces, interpenetrating between them and with some quartz crystals. A superb specimen.

Size: 11.0 x 6.8 x 6.3 cm.
Main crystal: 25 x 15 mm. (macla/twin)

Group of Sigloite crystals pseudomorph after Paravauxite, partially covering the rocky matrix. Paravauxite and sigloite differ chemically by the presence of a single water molecule. Sigloite is white to yellowish. The Siglo XX Mine is the type locality for Sigloite species.

Size: 5.5 x 3.5 x 2.5 cm
Main crystal: 9 x 2 mm

Fluorescent under long wave UV

Three prismatic Topaz crystals with well defined faces and edges, very transparent and showing a delicate and uniform pinkish tone. Very fluorescent. Implanted on a Quartz crystal matrix.

Size: 5,0 x 3,6 x 2,4 cm.
Main crystal: 5 x 4 mm (group)
Found in 11/2008

Fluorescent under long wave UV

From an not well-known Brazilian locality for the species, a colorful and aesthetic specimen formed by green malachite rosette-shaped pseudomorphs after azurite scattered over matrix of limonite. Good size and excellent shape.

Size: 5.5 x 5.0 x 4.2 cm.
Found in 2009.

One of a very few tourmalines I found in this old collection with this classic combination from the 1960s or 1970s: nice brilliant lustre, glassy surface, intense color zoning between pink to green. Parallel groth, terminal rhombohedrons and a crossing prismatic pink small crystal between them. This well-known pegmatite mine was discovered in 1991 and produced very colorful tourmalines. Nice gem.

Size: 2.2 x 1.2 x 1.1 cm

Col. J.M. Manchion (Barcelona)

Excellent specimen formed by a polysynthetic growth of hematite crystals, with an exceptional brightness. Rich in faces, defined edges and a good size for the species and the locality.
Rob Lavinsky said: "Splendent, complex hematite crystals form a striking specimen from this less well-known Brazilian locale. The majestic, large crystal, with numerous amazing faces is 3.5 cm and is nearly pristine. This fine piece is complete-all-around. Choice and uncommon material from the Larry Krause dealer stock". [go to mindat]

Size: 5.2 x 4.2 x 3.8 cm.
Main crystal: 3.7 x 3.5 cm.

A classic old-time specimen of hydroxylherderite, well crystallized, with sharp translucent idiomorphic monoclinic crystals. Lustrous and with a greenish-yellow tone. Associated with albite and muscovite from the Golconda pegmatite in Brazil. From Manchion Col., purchased in 1987 to Dr. Joan Viñals. Previously misidentified as herderite. Previamente mal identificada como herderita.

Size: 6.5 x 4.3 x 4.2 cm.
Main crystal: 3 mm
Found in 1987.

Col. Manchion #354, J. Viñals 04/1987,

A classic old-time specimen of hydroxylherderite, well crystallized, with sharp translucent idiomorphic monoclinic crystals. Lustrous and with a greenish-yellow tone. Associated with albite and muscovite from the Golconda pegmatite in Brazil. From Manchion Collection, purchased to Dr. Joan Viñals. Previously misidentified as herderite.

Size: 5.5 x 4.2 x 2.7 cm.
Found in ±1987.

Col. Manchion #364, J. Viñals 04/1987,

Group of very nice elbaite crystals, one of them with a good size, transparence and marked color zoning. They are accompanied by a rich group of clevelandite crystals very aerial disposed. We can observe groups of developed lepidolite crystals those give an aesthetic touch to the specimen.

Size: 6,3 x 5,4 x 3,8 cm.
Main crystal: 60 x 13 mm.