A big surprise at the Denver 2009 show was the appearance of what were widely being called among the world's best demantoid garnets; and in smaller numbers what are absolutely the world's best examples, without compare, of the rare topazolite garnet variety. These come from a remote deposit that is quite literally situated in a tidal-flooded mangrove swamp, near the town of Nosy Faly in Madagascar. Within a short time of their discovery, they had come to the attention of Dr. Federico Pezzotta of the Natural History Museum of Milano (after whom the new Madagascan beryl species Pezzottaite was named), an expert on both mining and the mineralogy of Madagascar. Dr. Pezzotta soon was able to facilitate the valuation and legal export of most of this material. In Tucson, he gave a talk on this locality, and the difficulties of mining there, from which the below information is taken with his permission. As well, through his sources I was able to obtain a very good mixed lot of specimens from this find, including both Demantoid and Topazolite garnets, in a variety of size and price points. ALL SPECIMENS WERE HAND-SELECTED FOR ME AT THE MINES, AND ARE (UNLIKE MOST) GENERALLY PRISTINE AND FREE OF DAMAGE!
The deposit is literally situated in a mangrove swamp, that floods each afternoon at high tide. The waters come in so fast, that I am told you have only a few minutes to clear the mining holes once it starts to come up from the ocean. And, the miners work til the last moment, to gain precious rock to sort later. Dr. Pezzotta has photos (below) showing both low tide with the working pits and their straw mat dividers; and then showing a higher rising tide...but could not ever get a shot at full tide because everybody must leave to walk 1.5 kilometers to "higher ground" ( - thus, nobody is around to take the photo at sunset when the tide is highest and completely covers all workings, huts, and barriers).
The garnet-bearing region on its surface measures about 400 x 400 meters, and is a hard rock to mine in. Nothing is on the surface, and the deposit was discovered completely by accident when locals found shards of garnet in the sections of rock exposed by ocean erosion lower down towards the coast. In this small region, now nearly completely denuded of its original mangrove covering, Dr. Pezzotta counted approximately 800 INDIVIDUAL mining holes, dug to various depths and without any regard for geology or mineralogy. They are dug quite literally at random and some people will dig for days to go down to depths (with HAND TOOLS only!), even after being advised that the rock may not be under them. 800 holes requires 800 teams of diggers, haulers, and sorters; and so you can imagine the crowd during working hours of some 2000-2500 people in this swamp, all flowing in and out with the tides of water. To reach the garnet layer, the miners have to dig straight down (literally, in vertical, rope "hanging seats"), 10-20 meters below the surface. When they hit garnet-bearing rock, they then branch sideways, each miner's group making their own tunnels where they wish and without apparent regard for the gradually honeycombing structure of the rock caused by other mining teams above, beside, and below them. Each "mining group" is actually a family or group of friends, working in teams to do this digging in a rush during the daylight hours, and when the water allows. Each team must start the day when the tide recedes, around 4 AM (after walking 2 kilometers from town), by spending 4-6 hours pumping water manually through a series of pipes and tubes to access their holes.
Then, they have several hours to frantically dig - hauling buckets out as fast as they can, for later sorting in the tidal pools by other team members. For the very ambitious workers, they all haul buckets and get to the sorting after hours - after carrying the heavy buckets to the high tide line 1.5 kilometers away. The problem is, obviously, that the holes fill each night with the tide. Between the tides and rainwater filling the holes, digging here is absolutely impossible in the rainy season and so all mining has ceased for the moment. It is an open question of whether it will be economical (and safe) to continue digging when the drier season of 2010 comes around. Given the conditions, the working with hand tools in small one-man holes, and the urgency of digging quickly, it is easy to see why so few perfect specimens are obtained. Most of what is recovered are smashed crystals simply hacked off the rock for any quick faceting value that can be yielded from the buyers in the wholesale gem trade. <
NOTE ON GEOLOGY: This deposit is unique. Studies by Dr. Pezzotta and his former graduate student Dr. Emanuele Marini, have confirmed that the main body of sedimentary rock here has been altered over geological time to a fine-grained garnet. The seemingly limestone matrix is so hard and strong for a reason - it is not limestone!
Per Dr. Marini: The matrix is mainly sedimentary rock (sandstone) metamorphised by lamprofiric dikes cross cutting the sedimentary deposit. On many matrix you see micricristalline garnet or the relict structure of the sedimentary rock. On few specimens you can see fossils. The demantoides formed in the fractures of the sedimentary rocks and yes, sometimes the matrix is micro-xls of demantoid with a growth of larger xls on them. Metasomatism is a serie of chemical reactions that bring a partial recrystallization with variation of its compounds: so, we can consider the demantoides a product of the metamorphism inducted by the intrusions of the lamprofiric dikes in the sedimentary rocks. All the garnets crystallized in the fractures are andradite, the Titanium member of the series. In some matrix closeups, the whiter style, you can observe some small sub-mm creamy xls. Actually these are andradite garnet as well, but with a conspicuous grossular component. The only associations are some quartz and (very rare and unusual!), stilbite.
(Federico Pezzotta specimen and photo)
A sinuous ribbon of glassy and gemmy, light olive-green demantoid crystals, to 1.5 cm across, is perched high on a white massive garnet matrix. A few of the crystals are also doubly terminated. The richness of the piece is good, as are the size of the crystals. The color is a little more olive than intensely green, but still at least comparable to most Italian demantoid of past finds, and pretty good by any standard. For overall aesthetics and richness in this price range, I thought this one of the better deals in the lot.
Perched aesthetically, high on a contrasting white matrix of massive garnet, is a single glassy, gemmy, light emerald-green, demantoid crystal measuring 1.35 cm in length. There are hints of incipient hopper growth present. Graceful and elegant, it is rare to find such a large and isolated crystal. The termiation is fully exposed and freestanding!
Nestled aesthetically in a massive, metamorphosed garnet matrix, is a cluster of glassy and gemmy, rich, cognac-colored crystals of topazolite. In size they reach to 1.5 cm across. A few crystals exhibit clear evidence of hopper growth, rarely seen in the garnet family of minerals. The crystals are extremely large for topazolite. They have superb lustre, and most are translucent enough to look through to the matrix underneath (as you can see in the photos). Interestingly.
Very fine, glassy and gemmy, olive-green crystals, to 1.8 cm across, lie flat on a massive, whitish garnet matrix. Some crystals are doubly terminated and at least two exhibit clear evidence of hopper growth, rarely seen in the garnet family of minerals. The crystals are extremely large for topazolite. They have superb lustre, and most are translucent enough to look through to the matrix underneath. Interestingly, this is a intermediate brown to green in color, and it is unclear whether to classify this particular hue as andradite variety demantoid, or variety topazolite.
Topazolite is a rare variety of andradite garnet, and this specimen hosts what surely must be among the larger crystals of the species. Clustered on contrasting matrix, this superb matrix topazolite specimen features glassy and gemmy, olive-green to cognac-colored crystals, to a whopping 2.5 cm across (HUGE). The large crystal, as well as one or two others, exhibits incipient hopper growth patterning, which is rarely seen in the garnet family of minerals. All crystals on the display face are pristine and complete! Also, even in the photos you can see they are 100% transparent, so gemmy you can look right through the garnets to the underlaying matrix.
Sitting on contrasting, massive garnet matrix is a drapery of interconnected glassy and gemmy, olive-green demantoid crystals to 1 cm across. They have superb glassy lustre! The large display face is very rich, and pristine except for one small ding in the middle, on a large crystal's side face. Several crystals exhibit clear evidence of hopper growth, rarely seen in the garnet family.
Glassy and gemmy, deep green, demantoid crystals, to 1 cm across, are scattered about aesthetically from top to bottom on massive garnet matrix. Several crystals are also doubly terminated. There are 5 crystals to about 1 cm, and the eye goes right to them. The piece as a whole is 3-dimensional and not a flat plate, as it appears in the photos. Really, neither are the garnets - they "pop out" quite nicely. The color here is slightly olive-hued, not quite the most rich green, but very good nonetheless. Lustre and transparency are high.In fact the color looks Italian, in hue , but with better lustre than usual. If this were Italian, it would be twice the price, from the classic locales there!
Nestled on a thin matrix of massive garnet is a continuous, flowing cluster of flat-lying , extraordinarily glassy and gemmy, olive-green demantoid crystals, to 1.5 cm across. The two largest crystals also exhibit clear signs of hopper growrth, rare in members of the garnet family. This is a splendid example from this find with VERY rich coverage, and in superb condition. It displays both vertically and horizontally to equal effect. In person, it sends out flashes from the dozens of crystals and hundreds of faces present (many quite large, recall). This much topazolite on one piece, is an extreme rarity by previous standards for the species, as well
Perched high on its matrix of sedimentary rock, which has been metasomatized (metamorphosed) to a slightly yellowish, microcrystallized garnet, is a cluster of glassy and gemmy, light emerald-green demantoids, to nearly 1 cm across. Many of the equant crystals also appear to be doubly terminated. Nice aesthetics, as they hang freestanding off the side of the matrix! Interestingly, the matrix reminds me of the shape of Texas, with the garnets shooting off to the top...THIS IS A BEAUTIFUL, larger specimen with an aesthetic crystal grouping overall, for the price
Sugary matrix of garnet is the host for a continuous coating of glassy and gemmy, green, demantoid crystals, topped by a 1.6-cm crystal. The largest crystal is aprticularly sharp, though it has a slight, small contact atop. Overall brilliantly sparkling, this is a great representative specimen from the find without breaking the bank.
This is a plate of intergrown, glassy and gemmy, green to olive-green demantoid crystals. In size they reach to 1.1 cm. The matrix is limestone metasomatized to garnet. Overall this is a brilliantly sparkling, bright, and showy specimen with a lot of color appeal and flash to it! The crystals are super bright and gemmy
A large thumbnail, perfect and balanced! Sitting perfectly on a matrix of metasomatized (metamorphosed from limestone) garnet, is a glassy and gemmy, jewel-like, richly green, demantoid crystal measuring 1.4 cm in length. It is complete ALL AROUND and has excellent lustre and color to it! Small parts of several back faces show unusual (for garnet) incipient hoppered growth patterning. Overall, an outstanding, fullsized thumbnail specimen! There are many small specimens from the find, yes; but few with such quality and balance overall to make them more than just a small sample, and rather a great thumbnail specimen.
Intergrown crystals of glassy and gemmy, olive green colored demantoid crystals, to 2 cm in length, form a solid plate on thin matrix. The crystals are elongated, and totally gemmy! They are glassy and transparent, so you can look right through them all, like little jewels. A beautiful and unusual plate from this locale
Highlighted by a large, unusually elongated, nearly 2 cm-long demantoid crystal, this matrix specimen has several, glassy and gemmy, light green, discrete crystals perched on the contrasting matrix. VERY fine example with good color, lustre, and translucency for the price and size ranges.
Perched aesthetically on top of the matrix are clusters of demantoid crystals to 1.5 cm in length. The crystals are glassy and gemmy and exhibit an olive green color. I really like the way each cluster is separated from the other, very 3-dimensionally, and shows many faces to maximum effect. Some incipient hopper growth is also noted on one or two crystals, which is unusual. The specimen is a large miniature or small cab , borderline in size. It showcases the crystals ery well and is MUCH better in person. The color is brown-olive, as if it is in between topazolite and demantoid in hue
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