Globular aggregates of white acicular crystals with a silky luster of oyelite, a rare calcium borosilicate, which are accompanied by very brilliant, transparent and well-defined calcite crystals. Nowadays these specimens are quite difficult to be found. It belongs from the Nicolau collection (Barcelona) and it is accompanied by the handwritten label.

Sold

Excellent specimen formed by numerous colorless acicular crystals of bultfonteinite, a rare hydrated calcium fluorosilicate, which is accompanied by beige prismatic crystals of olmiite, a hydroxysilicate of calcium and manganese. The specimen is very representative of these species. This is the type locality for olmiite. We include pooldervaartite because it is very common since it forms a series with olmiite.

220 € 150 €

Buy

Rich group of prismatic crystals of gaudefroyite, a rare calcium and manganese borate-carbonate, with an intense black color. They are accompanied by brilliant hematite crystals, along with barite, calcite and orange andradite.

Sold

Group of well developed ettringite crystals showing a pseudohexagonal prism, rich in terminal faces. This specimen has a rare toasted honey tone for the species and it is believed to be due to exposure to sunlight out of the mine. This sample is accompanied by many sharp manganite crystals, very brilliant, some twinned, and with an intense black color. An unusual specimen for this classic mine collected in 1985.

Very good specimen of bultfonteinite forming white acicular crystals, with prisms slightly beige to orange of olmiite. Two rare species from a mining area well known for systematic collectors. Accompanied by tabular celestine crystals. Good size and better quality.

Very good specimen of bultfonteinite forming white acicular crystals, with prisms slightly beige to orange of olmiite. Two rare species from a mining area well known for systematic collectors. Accompanied by tabular celestine crystals. Good size and better quality.

Excellent aggregate of acicular crystals of this uncommon mineral from a classic mine for the species. The sample dates from the early 1990s and is currently difficult to get pieces with this aesthetic.

This specimen shows parallel growths on a single axis, so typical of the finds from N'Chwanning mine. The tetrahedral crystals are brilliant with very well defined faces and edges and showing echeloned and skeletal growths. Good size for species.

The mine N'Chwaning II is well known worldwide for their specimens of olmiite or rhodochrosite, among many other mineral species. But this mine has also provided excellent samples of hydroxyapophyllites which are very different from the Indian specimens or any others. This is one of them, perhaps the best I've never seen.
A group of very aerial interpenetrated apophyllite-(KOH) crystals, very sharp. They show striated and defined pseudocubic prisms with small triangular faces of the tetragonal dipyramid on the dihedral angles. Very brilliant, translucent and with an excellent aesthetics. In addition, it presents isolated crystals on the matrix.

Let me add another "delicious" specimen of kutnohorita with manganoan calcite. Kutnohorite is a rare member of dolomite group, a calcium carbonate with manganese, magnesium and few iron... uncommon. In the specimen appears as acicular snowy white crystals on which have grown a large group of pink crystals of calcite with manganese. Good brilliance and calcite extremely fluorescent with reddish tone. In the back side we can observe a particular radial aggregates of kutnohorite, this is another shape of the species. We have both in the same sample... The aesthetics of the formations is unquestionable and the species is a classic hard to find.

This huge size specimen combines two very interesting species. On one hand we have spherical aggregates formed by radiated polysynthetic growth of poldervaartite, showing slightly curved top faces, with a very uniform beige and good luster. We would like to inform you that these specimens were found in the mine in late 2010 and were collected very few specimens. They were analyzed by SEM-EDS, and it was found that the external and surface crystals were mainly determinated as poldervaartite, while the inner concentric growths presents poldervaartite and olmiite mixture. This makes us confirm poldervaartite in this mine.
Only for this species this sample is excellent. But it is accompanied by xonotlite, an uncommon calcium silicate, in the form of fine needles, brilliance and flexible. A stunning combination. To increase its interest we can say that this sample is one of the few of this vug, from this popular South African mine. A great opportunity. We will send the analysis to the buyer.