Rosell Minerales

This sample comes from the Freiberg Bergakademie and is accompanied by a label from the end of the 19th century and beginning of the 20th. In this old label we can read that the specimen was identified as monazite. To corroborate this fact together with the other accompanying minerals, we proceeded to carry out analyzes by SEM-EDS. The results indicated that the crystals from honey to dark tones, with a vitreous luster, correspond to monazite-(Ce), which is accompanied by rare earth elements such as neodymium or lanthanum, replacing cerium. We also detected the presence of thorium, which explains why the piece shows some radioactive activity. In the potassium feldspar matrix, with quartz, we can observe small black crystals with a metallic luster that would correspond to members of the columbite-(Fe)-columbite-(Mn) series. We have also detected a thorium phosphate-silicate with REE and aluminum traces, with a composition similar to enalite, an independent member of the xenotime-thorite group, although we have not been able to confirm it. We will send the buyer all the analyzes that give this specimen a remarkable mineralogical value.

Size: 6.4 x 5.2 x 3.5 cm.
Found in s. XIX.

Freiberg Bergakademie
Analyzed specimen with report

Lorenzenite is a rare sodium titanium silicate found in nepheline pegmatites and syenites. In this specimen we can enjoy two bright, well-defined, brown crystals on matrix. A specimen from the Joan Astor Collection.

Size: 4.6 x 3.7 x 2.5 cm.
Main crystal: 10 mm & 7 mm.
Found in ±1990.

Col. Joan Astor (Barcelona).

Compact mass of purple chromian iowaite with minor inclusions of greenish-brown serpentine. Iowaite is one of the former minerals on the locality and mostly replaced by stichtite, which forms a similar aggregates but is more light, lilac coloured.

Size: 7.6 x 4 x 2.7 cm.

Achtaragdite is a unique, rare and poorly understood pseudomorph, from this remote Siberian locality that is the Type Locality for grossular garnet. It is a variety of the grossular-hibschite garnet series and is (technically, according to mindat) a hydrogrossular-chlorite-carbonate pseudomorph after what was formerly considered to be wadalite or some other rare hydrogarnet. The real precursor mineral for these pseudomorphs is now considered to be helvite.

Size: 4.2 x 3.4 x 3.2 cm.

Achtaragdite is a unique, rare and poorly understood pseudomorph, from this remote Siberian locality that is the Type Locality for grossular garnet. It is a variety of the grossular-hibschite garnet series and is (technically, according to mindat) a hydrogrossular-chlorite-carbonate pseudomorph after what was formerly considered to be wadalite or some other rare hydrogarnet. The real precursor mineral for these pseudomorphs is now considered to be helvite.

Size: 4.7 x 4.5 x 3.9 cm.

Achtaragdite is a unique, rare and poorly understood pseudomorph, from this remote Siberian locality that is the Type Locality for grossular garnet. It is a variety of the grossular-hibschite garnet series and is (technically, according to mindat) a hydrogrossular-chlorite-carbonate pseudomorph after what was formerly considered to be wadalite or some other rare hydrogarnet. The real precursor mineral for these pseudomorphs is now considered to be helvite.

Size: 6 x 4.3 x 3.6 cm.
Main crystal: 3 x 2.2 cm.

Dalnegorsk fluorite specimens are very difficult to photograph. This is the case of this piece formed by groups of cubic crystals, transparent, colorless, defined, with the edges of the cube beveled by the dodecahedron and inclusions of very curious shapes. It is accompanied by quartz crystals dotted with green chlorite. A very curious piece ...

Size: 6.8 x 4.4 x 4.3 cm.
Main crystal: 2.4 x 1.9 cm.

Group of prase quartz crystals, with good luster, very well defined and contrasting on a matrix covered by andradite crystals. A very aesthetic piece.

Size: 5.7 x 3.7 x 3 cm.

Doubly terminated crystal of prase quartz, with a very good size. It shows an intense green color and polycrystalline growths on the faces of the prism. Very aerial and esthetic specimen on a matrix rich in small andradite crystals and green hedenbergite needles. A very aesthetic piece.

Size: 7.6 x 7 x 5.7 cm.
Main crystal: 5.9 cm.

Achtaragdite is a unique, rare and poorly understood pseudomorph, from this remote Siberian locality that is the Type Locality for grossular garnet. It is a variety of the grossular-hibschite garnet series and is (technically, according to mindat) a hydrogrossular-chlorite-carbonate pseudomorph after what was formerly considered to be wadalite or some other rare hydrogarnet. The real precursor mineral for these pseudomorphs is now considered to be helvite.

Size: 3.8 x 3.3 x 2 cm.
Found in ± 1976.

Col. Joan Astor (Barcelona).

This is an exceptional sulphur specimen, both for this Russian mine and for the perfection of the crystals. In a cavity of the matrix several very well defined and doubly terminated crystals of sulphur are disposed, clearly showing the dipyramidal faces of different orders. With brilliance, translucent to transparent. With another group of crystals, one of them predominant, on sample side. On a matrix with scalenohedral calcite crystals. Specimens of this mine and with this fine quality are more than difficult to see. A sample from the Astor collection (Barcelona). You can find more information about this locality at geo.web.ru.

Size: 6.6 x 6.5 x 5.2 cm.
Main crystal: 1.4 cm.
Found in ±1998

Col. Joan Astor (Barcelona).

Extraordinary translucent laminar specimen of belomarinaite, an extremely rare sodium and potassium sulphate, of good size and with clearly visible crystalline forms. It refers to both chemistry and structure to aphthitalite. These sulfates are formed in saline deposits and in volcanic fumaroles, as is this case. This specimen comes from the type locality for the species. A unique opportunity for systematic collectors.

Size: 2 x 1.2 x 0.1 cm.
Found in ca. 2017.

Ex. M. Murashko specimen.
Type Locality

Specimen of alumoåkermanite (IMA2008-049) from the pegmatites of the Kola peninsula. Honey coloured. It is probably accompanied by species such as cebollite and juanite those form a whitish vein. A very rare species, very visible in the polished section. Good size. It comes from the southern part of the Kola Peninsula.

Size: 3.5 x 3.1 x 1.9 cm.

Bementite is a very rare manganese silicate, identified in the well-known Franklin mine (NJ, USA), where it has its type locality. This specimen comes from a mining area located in the central zone of the Pre-polar Urals, known for the manganese, rhodonite and magnetite mines. In this specimen we can observe aggregates of crystals with golden tones that stand out on the matrix. An opportunity for systematic collectors.

Size: 3.4 x 2.5 x 2.4 cm.

Excellent specimen of this rare potassium and zirconium silicate. It shows rich aggregates of hexagonal crystals, transparent to translucent, with an excellent brilliance. Colourless to slightly violet.They are disposed on a matrix of acicular aegirine crystals with a very dark green color, almost black. The Kukisvumchorr Mountains are in the central part of the Khibiny Massif. The area has a very interesting mineralogy, notable for its nepheline syenites.

Size: 4.2 x 3.5 x 2.8 cm.
Main crystal: 3 mm.

Very glassy opal specimen, with excellent transparency and yellowish bands. From an unusual area of Russia for this variety of quartz. It was acquired by A. Trigo (Mataró) in 1983, in Expominer Mineral Show (Barcelona).

Size: 4.5 x 3.9 x 1.5 cm.
Found in ca. 1983

Col. Antonio Trigo (Mataró).

Glendonite is the name given to the pseudomorphic calcite after ikaite. Ikaite, a hexahydrated calcium carbonate, was first observed in nature in the 1960s, at the seabed of the Ikka Fjord in Greenland. There, it precipitates due to the mixture of cold water submarine springs (3°C) rich in carbonates with seawater. Ikaite deposits are not usually found due to its poor stability, however, sometimes the rapid conversion of ikaite to calcite and water results in the generation of pseudomorphic calcite aggregates in the shape of the ikaite crystal (so-called glendonites). These calcite pseudomorphs directly replace ikaite above 4ºC.

Size: 6.1 x 2.2 x 1.7 cm.
Found in ca. 1995.

Col. Antonio Trigo (Mataró).

Very interesting blue-violet to lavender aggregates of johillerite, on matrix, and accompanied by black hematite crystals. Johillerite is a extremelly rare arsenate with sodium, copper and magnesium+zinc: Na(Mg,Zn)3Cu(AsO4)3. Only three localities worldwide: Tsumeb (TL), slags from Genna (Germany) and the Tolbachik volcano in Kamchatka. Johillerite forms a continuous solid-solution system with badalovite and nickenichite. Johillerite samples were obtained from the fumaroles of the North Breach of the great fissure Tolbachik volcano eruption (1975-1976). Cone took 44 days to form.

Size: 4.5 x 3.2 x 3 cm.

Aggregate of brown prismatic crystals of this rare niobium and tantalum silicate found in the alkaline pegmatites of the Khibiny Mountains, in this remote area of the Kola Peninsula. It is accompanied by pink aggregates of schizolite, an intermediate member of the pectolite-serandite series, and of lamprophyllite. Identified by Dr. D. Lisitsin.

Size: 5.6 x 3.8 x 2.8 cm.
Main crystal: 1.7 cm.

Lorenzenite is a rare sodium titanium silicate found in pegmatites and nepheline syenites. A lustrous, sharp, chocolate-brown crystals in matrix on this excellent specimen from the Joan Astor Collection.

Size: 4.5 x 4 x 3 cm.
Main crystal: 1.8 cm.
Found in 1994.

Col. Joan Astor.

Slab of native iron in mafic matrix. Specimen is tilted so reflections of sunlight make iron stand out from matrix. This iron could be refered to kamacite variety (content in Ni, see the apple green tones). It is accompanied by fayalite-forsterite and labradorite. Probably some cohenite is present in the sample. One side polished, natural the other. Analisys will be send to the buyer.

Size: 4.8 x 3.7 x 0.9 cm.

Analyzed specimen with report

Slab of native iron in mafic matrix. Specimen is tilted so reflections of sunlight make iron stand out from matrix. This iron could be refered to kamacite variety (content in Ni). It is accompanied by fayalite-forsterite and labradorite. Probably some cohenite is present in the sample. Both sides polished showing internal structures. Analisys will be send to the buyer.

Size: 4.9 x 3.5 x 0.5 cm.

Analyzed specimen with report

Doubly terminated wiluite floating crystal, a rare calcium, aluminum and magnesium silicate with boron. It presents two prisms of different order, the tetragonal dipyramid truncated by the pinacoid. With a interpenetrated crystal. Good size and deep green colour. Wiluite was accepted as a new species in 1997 belonging to the vesuvianite group. It comes from the type locality for the species.

Size: 2.4 x 2.2 x 1.9 cm.

Type Locality

Doubly terminated wiluite floating crystal, a rare calcium, aluminum and magnesium silicate with boron. It presents two prisms of different order, the tetragonal dipyramid truncated by the pinacoid. really good size and deep green colour. Wiluite was accepted as a new species in 1997 belonging to the vesuvianite group. It comes from the type locality for the species.

Size: 2.6 x 2.3 x 1.7 cm.

Type Locality

Doubly terminated wiluite floating crystal, a rare calcium, aluminum and magnesium silicate with boron. It presents two prisms of different order, the tetragonal dipyramid truncated by the pinacoid. Good size and deep green colour. Wiluite was accepted as a new species in 1997 belonging to the vesuvianite group. It comes from the type locality for the species.

Size: 2.3 x 1.8 x 1.7 cm.

Type Locality