On July 26 it was the pleasure of the DCGIA Chapter to have Lee Horowitz, M. Ed, CAGS, Gemologist of Peru Blue Opal Ltd. share his vast experience along with a mountain of both rough, cut stone and silver jewelry with us.
Lee’s partner and miner is Marcel Ryzenberg who also runs the cutting operations in Lima, Peru. Lee’s companies http://perublueopal.com/ are involved with miners and gemstone cutters with mines and factories for cutting gemstones in Lima, Peru and Pnohm Pehn, Cambodia. They do fancy cutting, faceting i.e. concave, millennium, checkerboard faceting and other cuts in Cambodia. They also represent rough gemstone materials from fellow miners in Peru and Bolivia and represent several miners in Zambia, Tanzania and Kenya.
Lee conducts stone identification, stone grading, stone evaluation, appraisals and sales for rough stone on behalf of miners and also provides cutting services. Together with his partners, they also perform gold assay, refining and sales on the world gold COMEX markets with thier miners.
Lee conducts many lectures concerning “Gemstones of Peru” and provided DCGIA with hands-on demonstrations of Peruvian gemstone rough, cut, beads, and finished products.
Lee provided samples and discussion of Peruvian Opal - blue opal including rough, cut, dendritic and picture blue opal, beads, faceted beads, and, 925 sterling were passed around and on display. firstname.lastname@example.org
Peruvian Blue Opal and Pink Opal are the flagship products. Because these Opals are found in the same areas as copper, most mines have transitioned from opal mining to copper mining. With the high price of copper, it is no longer cost effective to mine the opals. Additionally, many of the mines have been bought up by China companies and the new rich copper miners, and opal mining has stopped as they waite for higher prices for the gemstone rough. With China companies now owners, most of the gemstone rough goes directly to china, making availability nonexistant for everyone else.
There are 3 grades of Peruvian Opal: First quality, second-third quality and mine run. It is mined in Ica, Peru. The first quality is an even color, good top color for cabochons.
The second-third quality has more unevenness of color and more matrix in it. There may also be color striation as real opal will have color striation or unevenness of color due to the coloring. In the case of pink opal it is colored by a clay that surrounds it or it is usually found in, a mineral called palygorskite.
Peruvian Pink Opal has a hardness of 6 versus Peruvian Blue Opal which is 5.5 hardness; making the pink opal some of the hardest opal in the world. Some pink opal also comes from Mexico and some other places in the world.
Some of the very top material is saturated with color actually making it reddish. These are rare pieces, There also has been a little drusy. Which is a coating of fine crystals on a rock fracture surface, vein or within a geode found in the pink opal but mainly for collectors and in small areas.
The Pink Opal is high in silica in which this opal is almost a pink chalcedony but it is opal and has opal cleavage. There is never a water problem with pink opal and so it is stabile. In some cases, there may be a limited amount of dying done. However, this is typically done overseas, usually in India or China. Top color pink opal is expensive rough material. Mine run pink opal is whitish-brownish-greyish with slight pink coloring and washed out color and is usually made into beads and sold in tonnages overseas and can sometimes be dyed. Unfortunately, as top color disappears on world markets, Lee believes that this stone will eventually go the way of blue opal with mine runs being totally dyed and many imitations of top color.
Some new and exciting stones include a new find of what Lee believes is blue aragonite which looks like larimar and is sold by some miners in Peru as such. Lee is also testing for other materials. Additional new materials include banded pink rhodocrosite, leopard stone with a super pattern, bubblegum pink rhodonite, black jade and much more.
Summary by Charlie Marts
Photos by Melanie Marts, GG