San Juan de Rayas Mine - Level 407
2.2 x 1.3 x .6 CM (thumbnail)
Branching crystals of Acanthite forming a tree-like thumbnail with very bright metallic luster. Complete all around, undamaged and pretty. A very good yet still affordable Silver specie from the famed Guanajuato deposit. This area has been continuously mined for Silver since the discovery in 1585, and this was the world's largest producer for many years. Amazingly there are still a few operating mines and Silver minerals are still found though far less than before.
Milarite on Valencianite and Quartz
Valenciana Mine (Mina La Valenciana), Municipio de Guanajuato
7.8 x 5.8 x 5.4 CM (cabinet)
One of the more uncommon Beryllium Silicate species, Milarite is a real "mineral collectors" specie. This piece is from the find some decades ago in Guanajuato, Mexico. The Matrix is a mix of Quartz and Valencianite (variety of Adularia). The Valencia Mine is the type locality for the Feldspar and was the source of these small bright yellow Milarites which were big news in the mineral world. This piece has several very small crystal and one a bit larger (about 8mm). These are flat habit and the structure is not as evident without good magnification. A fair example of the find that is not crazy expensive.
Polybasite on Acanthite
Guanajuato, Municipio de Guanajuato
3.2 x 2.4 x 1.7 CM (thumbnail)
A killer specimen with exceptional form, the main crystal being textbook perfect, sharp and perfectly defined. Formerly in the collections of Carl Acosta and Brett Keller, this is just barely within the size limit to be classified a thumbnail. The Acanthite matrix is the "melted" look type and is a fine contrast to the large Polybasite. Displays well from either side, what we consider to be the front or best view has a nice metallic patina. Most of the Polybasite we have seen from Guanajuato is more crude or has overgrowths of Pyrite, this is just a superb example of the specie and extraordinary for the locality.
Ruby Silver crystals (Polybasite) are nicely grouped on the Quartz matrix. Several small Polybasite crystals with classic hexagonal form are present as well, these covered by druzy Chalcopyrite. Esthetic, lustrous and in excellent condition with no visible damage. With strong lighting the translucent ruby color is revealed but under normal display these look like metallic black crystals. Very clean, the polybasite shows well formed independent crystals even though there are clustered in groups.
Apophyllite - pink
Guanajuato, Municipio de Guanajuato
8.7 x 6.8 x 4.6 CM (cabinet)
A fine crust of Apophyllite crystals with a light pink color and glassy luster. An older piece from Guanajuato with the typical Quartz matrix having amethyst zoning. From the Stanek collection (Brno, Czech republic) we do not see many Guanajuato specimens available, most Mexican pinks are from Zacatecas or Charcas but these were found long before those later finds. In super fine condition.
Acanthite and Polybasite on Quartz
San Juan de Rayas Mine, Municipio de Guanajuato
5.7 x 4.4 x 2.3 CM (cabinet)
A melted look sculpture of Acanthite crystals on Quartz also holds a few small Polybasite crystals in sharp hexagons. Choice older piece from the San Juan de Reyas mine in Guanajuato. In excellent condition as seen and with a nice dark metallic patina. Under 20 X magnification I can see glints of blood red color that indicates at least a tiny bit of Ruby Silver (Pyrargryite) is also present but very small.
A classic and fine old specimen of the Adularia variety Valencianite. Ex Harvard University, Ken Hollman and Terry Szenics collections. From the Valenciana Mine(Guanajuato, Mexico) this has sizable crystals to 2.7 CM,and is in perfect undamaged condition. A dusting of small clear Quartz crystals and a few micro Sulfides ads some character as well.
Calcite on Quartz (Amethyst)
Mina Peregrina, Guanajuato
8.4 x 6.4 x 4.1 CM (cabinet)
Bright glassy clear crystals of light pink-violet Calcite perched on a contrasting Amethyst matrix. Classic material from Guanajuato, this is quite eye-catching. In excellent condition, there is a single clean repair that is super hard to find, that needs to be mentioned. This keeps the price low yet this displays like it cost far more.