Bournonite!
A group of exceptional bournonite specimens from a recent find in Bolivia. Many of these pieces have lusters that are about as good as one could hope for from the species, and display excellent cogwheel form. Bournonite from this mine tends to have somewhat tarnished, altered surfaces, or crystals that are somewhat thinner. In fact, the last time this mine produced particularly good lustrous crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned, nor did I see any on matrix.
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19BL01 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
14.5x 10.1x 5.6 cm
$4300
Simply put, this is a spectacular example of bournonite. This piece has sizable, blocky crystals displaying excellent "cogwheel" form, with a luster that probably cannot get any better for the species. The main crystal is well exposed, and unusual thick.
It is an amazing piece for the species-- I do try to keep the extra salesman-y BS to a minimum in my descriptions, but this really is a great specimen, and compared to what the price would be in Tucson or on other websites, I would say this is very much on the reasonable side.
The last time this mine produced particularly good lustrous crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned, nor did I see any on matrix.
Eat your heart out Cornwall.
19BL02 Bournonite on Quartz
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
5.1x 4.9x 4.6 cm
$600
One of only two examples of bournonite crystals with quartz that I was able to obtain. This piece features a cluster of crystals with exceptional luster and textbook "cogwheel" form, perched on a matrix shared by numerous colorless quartz crystals. Very well balanced with a quite "refined" appearance. There is only minor edge chipping, but you have to look closely to see it. Probably in my top 3 favorites for the update.
The last time this mine produced particularly good lustrous crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned, nor did I see any on matrix.
19BL03 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
4.4x 3.2x 2.5 cm
$585
A beautiful example of bournonite from Machacamarca-- this piece features a damage-free, textbook "cogwheel" perched on its matrix in such a way that lends exceptional visual balance to the piece. Even the dark coating on the matrix (tarnished pyrite or freibergite?) seems to dim the surrounding material in order to make the luster of the bouronite stand out better.
The big one earlier in the update is certainly the best, but this is my favorite.
19BL04 Bournonite on Quartz
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
7.0x 5.0x 4.7 cm
$465
A nice example of bournonite on quartz. This was one of two examples I was able to get with a strong quartz association-- this one has a lustrous group of "cogwheels" nestled near the edge of the quartz cluster. The metallic bournonite and have a very nice contrast, and the association gives a very Herrodsfoodt-y appearance... except the faces of the bournonite aren't nearly as messy as the average Herrodsfoot piece.
19BL05 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
5.1x 4.9x 3.8 cm
$485
A cluster of large, blocky bournonite crystals from a recent find. This is a great example showing textbook "cogwheel" form with crystals that are somewhat larger than the usual.
The last time this mine produced particularly good lustrous crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned.
19BL05A Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
3.4x 3.4x 2.6 cm
$395
A beautiful and exceptionally lustrous cluster of bournonite "cogwheels" from a recent find.
The last time this mine produced particularly good lustrous crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned, nor did I see any on matrix.
19BL06 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.4x 2.0x 1.7 cm
$225
There were a number of thumbnails in this group, but in my opinion, this was the best. The crystals display textbook "cogwheel" form, with great luster and are relatively thick for the size-- the vast majority of what comes from this mine tends to be somewhat thin. And most importantly, the piece is just all around visually balanced exceptionally well.
19BL07A Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
6.2x 3.9x3.9 cm
$435
A cluster of unusually bright and lustrous bournonite crystals on matrix. The pieces from this find really stand out for their combination of thickness and luster-- the brightness of these crystals is not something that is common from this location-- they tend to be tarnished or have overgrowths of sphalerite or miscellaneous antimony minerals.
The last time this mine produced particularly good crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned, nor did I see any on matrix.
19BL08 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
6.6x 4.0x 3.9 cm
$360
A nice example of bournonite crystals perched on the top of their matrix.
19BL09 Bournonite with Tetrahedrite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
13.5x 8.6x 4.4 cm
$560
A large and interesting sulfide specimen from Machacamarca. It has a couple very lustrous bournonite crystals to just over an inch, but I would say that the real star of this piece is the tetrahedrite-- you don't often see such good crystals of that species from Bolivia. There is also some wacky pseudomorphing or alteration going on-- I'm not sure exactly to what, but it looks like some of the tetrahedrite was int he process of slowly being etched and recrystallized into something else. Possible freibergite present, I but can't say for sure.
19BL10 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
4.7x 4.2x 2.0 cm
$195
A beautiful bournonite crystal standing up from the edge of its matrix.
The last time this mine produced particularly good lustrous crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned, nor did I see any on matrix.
19BL11 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
4.0x 2.2x 3.6 cm
$165
A nice cluster of bournonite crystals on a sliver of matrix, from a recent find.
19BL12 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
5.5x 3.2x 3.6 cm
$275
A nice example of bournonite, with a hefty crystal sticking out of its matrix, from he recent find.
19BL13 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
3.8x 2.8x 1.6 cm
$195
A nice cluster of lustrous and very well defined bournonite "cogwheels" from a recent find that has produced exceptional examples of the species. Looks good from multiple angles.
The last time this mine produced particularly good lustrous crystals was 2012-- there was another find of large blocky crystals around 2015, but they didn't have much going for them as far as luster was concerned, nor did I see any on matrix.
19BL14 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.7x 2.4x 2.1 cm
$165
I would consider this to be one of the better thumbnails from he group-- it is a cluster of relatively thick and lustrous bournonite cogwheels. There is minor edge chipping, but the arrangement makes for a rather beautiful and well balanced piece that is displayable from multiple angles.
19BL15 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
3.7x 2.2x 2.9 cm
$135
A nice blocky and rather lustrous bournonite crystal from a recent find. Not perfect (chipped on the top and contact not he bottom/back) but a good example from the find.
19BL16 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.3x 1.7x 0.8 cm
$75
A nice thumbnail sized example of a bournonite "cogwheel" from Bolivia. Not perfect, but displays exactly as shown.
19BL17 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.4x 2.1x 0.85 cm
$85
A nice thumbnail sized example of a bournonite "cogwheel" from Bolivia... it kind of reminds me of a coin.
19BL18 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.0x 1.7x 1.4 cm
$68
A nice thumbnail sized example of a bournonite "cogwheel" from Bolivia.
19BL19 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.8x 2.7x 1.7 cm
$135
A beautiful cluster of lustrous bournonite crystals from Bolivia, with a sliver of matrix.
19BL20 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.3x 1.9x 1.7 cm
$75
A nice thumbnail size dimple of bournonite from a recent find in Bolivia. This piece has contacts on the back and bottom, but displayed as pictured in the first image it would actually look quite nice in a Perky box.
19BL21 Bournonite
Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
2.6x 2.x 2.1 cm
$125
A nice thumbnail sized example of a bournonite crystals from Bolivia.
19BL22 Phosphophyllite
Hauayllani Mine, Machacamarca District (Colavi District), Saavedra Province, Potosi Department, Boliviah
4.2x 3.7x 2.0 cm
$200
A nice example of rare phosphophyllite from a find made several years ago in the Machacamarca District, at a different mine than the bournonites, but nearby. Phosphophyllite is best known from the old finds at the Unificada Mine— those pieces command prohibitively exorbitant prices, and until this find (with the exception of a few odd type locality pieces from Germany) the species was pretty much outside the price range of most collectors— and even those who could afford them had to wait for a decent piece to become available.
Whenever I read or hear a sales pitch for a phosphophyllite, there is inevitably a reference made to this being a “holy grail” species for collectors…. If the Unificada pieces are the “holy grail” then these Machacamarca specimens are more of the styrofoam cup version of the “grail”, but hey, it’s a phosphophyllite.
