• Created By : 27-Jul-2017
  • Write By: tmmadmin
  • Published In: Your Collection
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Buyers scour the wholesale showroom at Top Gem Minerals in Tucson, looking for deals.  Eric Greene photo

Mineral collecting is one of the greatest hobbies in the world. I often find that the word ‘hobby’ seems inadequate for what is a lifelong, all-consuming passion for many serious mineral collectors. For as many reasons as there are for collecting minerals, there are ways of acquiring them. Some people are die-hard field collectors and their collections reflect many hundreds of hours swinging hammers and chiseling outcrops, traveling mine-to-mine in search of fine mineral specimens to add to their cabinet. Others attend club meetings, field trips, local rock swaps, and silent auctions where they might spend $10 or perhaps $20 on a modest specimen for their collection. For such collectors, the enjoyment of the hobby may be largely related to the social aspects- the meetings, the club shows; the myriad ways in which we engage and participate with our tight-knit community of fellow rock nuts. For others still, the thrill is in the hunt for a true ‘trophy specimen’ whose value can easily climb into the tens or hundreds of thousands of dollars, and whose acquisition may feel more like an initiation into the secretive and zealous world of high-end mineral trading.

  • Created By : 21-Jun-2017
  • Write By: tmmadmin
  • Published In: Mineral Species
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Penas Blanca Emerald Mine, Boyacá Department, Colombia

At the 2017 edition of the Tucson Gem and Mineral Show, one of the new introductions and stars of the show was chrome fluorite from Colombia's Penas Blanca Emerald Mine. This mine is on the northern edge of the Western Emerald Bearing Belt, or Boyaca Belt, north of Muzo. It is unique for its absence of pyrite and other sulphides and the presence of fluorite. The mine also produces notable calcite, barite, dolomite, water-clear quartz, and of course, emeralds. The locality is near Mun. de San Pablo de Borbur, in the Vasquez-Yacopí Mining District, Boyacá Department, Colombia.

In February 2014, in the last week of the usual rush of a Tucson Show, Bob Jackson invited me to join him for a dig at the La Fluorita Dulcita claim. Bob is a well-known field collector from Washington state, perhaps best known for his work at Spruce Ridge in the Cascades and the Rock Candy Mine in British Colombia. In 2010, a rancher in Cochise Co., Arizona had invited Bob to check out a fluorite prospect on his family's property. The result was a mineral lease, and from 2011 to 2014, Bob mined the property for fluorite specimens, using an air drill and explosives. One of the conditions of the lease was that the exact location had to be kept secret, to discourage trespassers. I was duly sworn in, and made the trip without a blindfold.

We are sad to report that the Rogerley Mine is officially closed. Located in the village of Frosterley in County Durham, England, the mine was operated commercially for mineral specimens in the 1970s, and then was run by from 1999 through August, 2016. The mine workings followed an adit extending northward along the Greenbank vein at the High Flats horizon of the Great Limestone. Colorful specimens of green fluorite crystals, some associated with galena, were recovered from discontinuous mineralized flats on both the east and west sides of the vein.

The Capillitas Mine is the believed to be the world's largest mass of rhodochrosite - famous for its unique formation, occurring as stalactites and stalagmites. Rhodochrosite is a manganese carbonate mineral with the chemical composition MnCO3. The mine is located in the Andalgalá Department, Capillitas Province, in northwestern Argentina.

Mined since Incan times, the polymetallic sulphide veins at the Capillitas Mine were worked in the 17th century for silver, and later for lead and zinc. Today, sulphides extraction is no longer economical, but the mine is still being worked for and lapidary material for specimens and carving, producing 100-200 tons of material a year. The banded rhodochrosite is often sliced and polished into slabs for collectors.

  • Created By : 20-Apr-2017
  • Write By: tmmadmin
  • Published In: ROOT
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Chalcopyrite is a brassy yellow mineral with the chemical composition CuFeS2, or copper iron sulfide. It is found in most sulfide mineral deposits around the world. Chalcopyrite loses its surface metallic luster and brass-yellow color when it weathers, changing to a dull, gray-green color. When acids are present, the color can become brilliantly iridescent purple, violet, blue or green. Chalcopyrite is most easily recognized by its brassy yellow color, metallic luster, and high specific gravity, which give it an appearance similar to pyrite and gold. Unlike these minerals, chalcopyrite is brittle and has a unique greenish-gray streak, and unlike pyrite, is easily scratched with a nail.