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ETTRINGITE crystals from the KALAHARI MANGANESE FIELDS
These specimens come from a remarkable single pocket, perhaps from the early 2000's, and are distinct to my eye from previous finds of this species. I bought the entire contents of the pocket (under 100 pieces), so far as I know, from which we selected about 3 dozen of the best pieces to offer here. I am told that this pocket was actually found some years ago and hoarded, to see if more would follow. Obviously, nothing like this has come out since, and the combination of habit, size, color, and association remains VERY distinct from past finds of this material!
NOTE ON SPECIES DESIGNATIONS: Ettringite forms a chemically-related series with Charlesite and Sturmanite, and to be precise each of these crystals is certainly going to be a zoned mix of the species. In particular, these crystals almost all exhibit a clear inner core which is colorless, indicating possible species zoning from the center to the outer layers. From prior experience and investigations, I have been told that generally the crystal cores are ettringite and charlesite, and the lemon-yellow colored portion is mainly ettringite. Most brighter yellow specimens are thus classified, though sturmanite may indeed be present to some extent as well. Although XRAY must be done to distinguish with 100% certitude, most sturmanite has a different (more squat and disclike) crystal habit, and these crystals resemble in form pieces most often labelled as "ettringite." So, pending laborious analysis I will attempt to get worked up while at the Tucson show in collaboration with a University, I am labelling these as Ettringite: with ettringite and charlesite cores, for sale before the show
NOTE: Nearly all specimens have identical color in person, unless otherwise stated. The color is a fairly strong lemony-yellow hue, classic for the species but here combined with unusual translucency which causes them to look a little more pale in the photos, than they do in person.
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This is a huge specimen, with more ettringite in one place than I have ever seen. It is really subtle in its beauty, with oyelite between the cracks in the crystals, providing a white webwork background on which the powder-lemon-yellow crystals stand out all the more dramatically. There is some damage to the edges of the large crystal cluster, where peripheral-facing tips are missing or there is a contact point. But the core clustre is very 3-dimensional, gemmy, and capped by the best terminated crystal: The large crystal in the middle is 10 cm tall, and has a freestanding termination. Charlesite is a close relative of sturmanite and ettringite, and my understanding is that most crystals of either of the two yellow and more common species are actually zoned, and are thus partial charlesite. However, this crystal seems to have a pure, clear core which i suspect is charlesite, perhaps pure. (not analysed). Unusual, in any case! Even more than on other specimens in this lot, many crystals here appear to consist of a white charlesite crystal with an outer layer of powdery-lemon-yellow ettringite atop, from what i am given to understand about how these species form in a related series. The outer layer of colored ettringite is very thin, under 1 mm, and most of this crystal is therefore clear and colorless. These larger crystals (but not the smaller ones) are slightly etched and matte compared to other crystals in this pocket, perhaps part of the phenomena revealing the clear cores. I am sure all in this pocket are zoned in some degree to charlesite and/or sturmanite; but this one is distinctly different, with the totally clear core showing so nicely. A MUSEUM PIECE, in both size and visual impact, even for the public who will not care about the fascinating chemistry revealed here in a gigantic specimen of a very rare species. The backside of the specimen has hausmannite, hematite, and oyelite. 1.3 kilos.
A cute, 3.9-cm-tall crystal : it is lemon yellow, translucent, and complete all around save a small contact near the base in rear, overall an excellent example of this style and pocket
A truly outstanding, lemon yellow crystal measuring 4 x 1.7 x 1.5 cm, perched against a matrix of hausmannite, makes for one of the more impactful and memorable miniatures in this lot. The black on yellow color contrast is REALLY stark and exciting, and I think overall the balance of the two species makes the piece special. Pristine, complete all around, this is a competition grade miniature
This is a dramatic, pyramidal cluster of 3 intergrown crystals to 7 cm in height, leaning in upon one another to create what looks like a work of sculpture more than a minerals. Hand-down, one of my favorite pieces in this pocket, as reflected in the price admittedly. This piece has superb lemon yellow color, and combined with its translucency is almsot ghostly in effect. It has a medium lustre typical of this pocket but more lustrous than most of the species, and examplifies the fat, tapered crysatl form of this find. It is a world class example of a very rare species, bright yellow, and yet such things do not break the bank to own, even when at the top of their game, compared to tourmaline or aquamarine or even fluorite and calcite these days. I regard such exemplary rarities as this, therefore, as very special pieces, and good investments for the money into something truly unique and special. This may not be over 10k, in other words, but it is a MAJOR example of the species and would be a highlight, with unusual color and geometry that make it leap out, in any collection.
A slender single crystal, complete all around, that exemplifies the qualities of this find: translucency, shimmering surface lustre, and unusual tapering form. It has a pastel lemon-yellow color. It is hard to explain or convey in pictures, but there is a certain ethereal quality to these specimens that makes the crystals look "soft" and unusual compared to most other large crystalline species.
A fat single crystal, complete all around, that exemplifies the qualities of this find: translucency, shimmering surface lustre, and unusual tapering form. It has a pastel lemon-yellow color. It is hard to explain or convey in pictures, but there is a certain ethereal quality to these specimens that makes the crystals look "soft" and unusual compared to most other large crystalline species.
A sharp miniature with vivid contrasts! This clustre of upright ettringites is host to a crust of brilliantly sparkling, micro-hausmannite crystals on one side. All is perched on a thin shard of caclite and hausmannite-covered matrix. A really nice, elegant miniature, with good color and translucency, representative of this new find.
A very aesthetic large thumbnail specimen (or small miniature), one of few apparently saved and complete, featuring crossed crystals of soft lemon-yellow color, and translucency characteristic of this pocket
A very aesthetic large thumbnail specimen, one of few apparently saved and complete, featuring a 3-cm, doubly-terminated crystal atop a soft, oyelite-covered knoll of matrix. The crystal features pastel lemon-yellow color, and translucency characteristic of this pocket
This is a very aesthetic, freestanding cluster of several crystals, with an accent of stark black hausmannite as a hat, atop! The hausmannite draws the eye to the flat, fine termination. Complete all around, this is a really unusual piece, overal. The crystal features soft lemon-yellow color, translucency, and a good surface lustre for this species.
This checkmark-shaped specimen is a cluster of two complete, pristine crystals (to 4 cm), attached at their base. I have taken the measurement as shown in the photo of it shaped like a "checkmark," to be clear. It is a really elegant and unusual piece, overall! A superb, showy miniature featuring soft lemon-yellow color, translucency, and a good surface lustre for this species.
A sharp small miniature specimen, featuring a doubly-terminated crystal to 2.5 cm, perched atop or to front, as you might display it either way. A superb, showy miniature featuring soft lemon-yellow color, translucency, and a good surface lustre for this species. Overall very aesthetic, as the crystals are perched on soft oyelite-covered matrix
This is a very aesthetic, freestanding cluster of several crystals, with an accent of stark black hausmannite in the middle! A superb, showy miniature featuring soft lemon-yellow color, translucency, and a good surface lustre for this species. For overall aesthetics in a miniature, this is one of my favorites in this pocket.
Perhaps my personal favorite of the lot, this is an elegant, starkly dramatic single crystal of 6 cm length shotting up from a perfectly trimmed bit of accenting matrix that serves as a pedestal. The matrix is a thin plate of manganese gossan covered on one side by a rolling carpet of soft oyelite; and on the other by a brilliantly sparkling layer of micro-hausmannite crystals. It has a wonderful and unusual (compared to other species) lemony-yellow color, slightly pastel but not pale at all. It is hard to explain or convey in pictures, but there is a certain ethereal quality to these specimens that makes the crystals look "soft" and unusual compared to most other large crystalline species. And, this is a rather large example for this species. Remarkably, it is COMPLETE all around! Although past finds of ettringite have produced a few crystals of this size, and smaller ones with more intense color, these leap out at you from a case as something truly unusual, and this piece has aesthetics which take it to the next level still. I think, overall, these ghostly, deep yellow crystals, especially specimens like this on matrix, leap out from any collection as there are few species with such a color.
A sharp 2.6-cm-long, doubly-terminated crystal sits atop this richly covered matrix knob, overhanging a carpet of sparkling micro-hausmannite crystals. Although not large for the pocket, this is a good matrix ettringite piece of unusual contrast, and one of our few matrix miniatures
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Rob Lavinsky, rob@irocks.com
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share specimen![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-205mm_0591.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-205mm_0591.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-205mm_0586.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-205mm_0586.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-39mm_0697.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-39mm_0697.jpg)
![Ettringite with Hausmannite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-45mm_0646.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-45mm_0646.jpg)
![Ettringite with Hausmannite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-45mm_0647.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-45mm_0647.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-7cm_0603.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-7cm_0603.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-7cm_0604.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-7cm_0604.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-35mm_0696.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-35mm_0696.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-35mm_0698.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-35mm_0698.jpg)
![Ettringite with Hausmannite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-54mm_0661.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-54mm_0661.jpg)
![Ettringite with Hausmannite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-54mm_0660.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-54mm_0660.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-27mm_0754.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-27mm_0754.jpg)
![Ettringite on Oyelite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-35mm_0752.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-35mm_0752.jpg)
![Ettringite with Hausmannite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-49mm_0667.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-49mm_0667.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-47mm_0759.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-47mm_0759.jpg)
![Ettringite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-47mm_0760.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-47mm_0760.jpg)
![Ettringite on Oyelite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-37mm_0757.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-37mm_0757.jpg)
![Ettringite with Hausmannite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-49mm_0682.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-49mm_0682.jpg)
![Ettringite with Hausmannite and Oyelite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-1021a.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-1021a.jpg)
![Ettringite with Hausmannite and Oyelite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-72mm_0613.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-72mm_0613.jpg)
![Ettringite with Hausmannite and Oyelite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-1021b.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-1021b.jpg)
![Ettringite with Hausmannite and Oyelite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-1021c.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-1021c.jpg)
![Ettringite with Hausmannite from Nchwaning Mines, Kalahari Fields, South Africa [db_pics/new2010/Ettringite-Kalahari-Namibia-55mm_0740.jpg]](db_pics/new2010/Ettringite-Kalahari-Namibia-55mm_0740.jpg)