Montebrasite is the Hydroxyl analogue of Amblygonite and are virtually impossible to distinguish visually, and almost always need chemical identification. Fine gem crystals of Montebrasite are not very common, despite the fact that the crystals can be huge. Most gem quality Montebrasite crystals are small, and clean stones are not often very large. This stone is a very good sized Montebrasite gem with nearly eye clean clarity and a "Freeform" cut. One does not encounter gems of this size and quality often on the market, and it would make a great addition to a colorless stone collection or perhaps a stone to add to a Brazilian gem suite.
6.2 x 1.4 x 0.4 cm. A HUGE, fishtail-twinned, lightly frosted, transparent, tan montebrasite crystal from the famous Sapucaia Mine of Brazil. Montebrasite is a rare lithium phosphate and this is a superb, large, and extremely elongated example of the species. Pristine. Ex. Carl Davis Collection and accompanied by a Wards label circa 1950s.
11.3 x 7.6 x 4.9 cm. This specimen features a twinned, bi-terminated montebrasite crystal measuring about 3 x 3 cm, perched in matrix of lepidolite. The crystallized lepidolite is in long tube-like forms. Most unusual matrix and a rare association as far as I have seen. The montebrasite is complete, although partially etched, and sticks up like a breaching whale tail from the matrix for a sharp contrast. The specimen, as a bonus, is rich in globular aggregates of the rare species zanazziite, clustered in and amongst the lepidolite and albite matrix.
These HUGE CRYSTALS have a pleasing pale yellow color to them and are translucent. They have been XRAYED and are montebrasite and not the species amblygonite with which there is often confusion in labelling. Admittedly, there were some on matrix, but they tended to be clunkier overall and were priced higher, so I just went for one nice example of the single crystals. This one has a fully developed, wonderful top termination. The piece displays nicely from either side, though one side has a rich coating of kosnarite on it (orangey, small xls) occuring as a thin attached plate that can be popped off if desired. Interesting and attractive new material from Brazil! 8.5 x 7 x 3 cm
9.6 x 9.3 x 6.9 cm. This is a fist-sized cluster of thick, fat, intensely yellow montebrasite crystals with minor cleavelandite association. Clusters are very rare, and these chunky, deep-colored crystals really combine to make a fine overall specimen. The piece is not pristine, as it has some contacts around the edges and a few trivial dings on the display face as well. In person, this material from a modern find at this old locale has a rich color, almost an inside glow to it, that is hard to convey in photos. Weighs 577 grams.
6.4 x 4.7 x 4.3 cm. This is a large, pinkish-yellowish-tan, partial montebrasite crystal (originally labeled as "amblygonite") from the much less well-known Tamminen Pits at Greenwood. Ex. N.A. Wintringham Collection and comes with a faded August, 1948 card.
3.4 x 3.1 x 1.7 cm. Collected shortly after the famous blue-green tourmaline pocket. In 1974, Bob Whitmore collected a small pocket hosting several crystals of Montebrasite, such as this one. Ex. Robert Whitmore Collection.
ex. Robert Whitmore
Collected shortly after the famous blue-green tourmaline pocket, this is yet another abberrant, incredible find for the locality, but one of which I was completely ignorant until now. In 1974, Bob Whitmore collected a small pocket hosting several crystals of Montebrasite, such as this one (it still has pocket clay attached, not yet cleaned stark white with acids). These crystals have to rank as the best for a US locality, and I do not think were superceded until Brazilian material came out some years later. This is the best miniature in the collection, although a shockingly large, equally sharp and well terminated crystal of 12 cm also was present in the collection. That larger one is now in the Smithsonian Collection, so this fine miniature is in good company. According to Dr. Vandall King, these are now classified as Montebrasite , though Whitmore's label from 30 years ago notes it as Amblygonite.
ex. Dr. Steve Smale
When I first saw this lemon-yellow crystal, I thought it was a particularly intense orthoclase from Madagascar. I next guessed a bizarre twinned Dolomite from Brumado. I only drifted to guessing Montebrasite/Amblygonite on try #3. This is a stunning crystal with a color , lustre, and gemminess that is WAY beyond anything you normally see for the species. It is fat and, I believe, twinned. It has an intense yellow-citrine color to it. Steve Smale, before exchanging this to me in a deal, had owned this for some time, and got it directly from the eminent dealer Carlos Barbosa (now deceased). He considered this to be the finest crystal for his taste, of the species. While there may be larger examples, for sheer quality, I have not seen better either. Note that this piece was analysed to be sure it is in fact Montebrasite, and not Amblygonite. This specimen was featured in the exhibition "MINERAL DREAMS: Brazilian Gem treasures" at the Munich show of 2010. Joe Budd Photos - and yes, the color is absolutely accurate and incredible!
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