Since many years the trade name »Snakeskin Agate« applies for a beige chalcedony with characteristic white lines. (fig. 1).
In 2005, very similar looking material in bright orange colors appeared on mineral fairs, being sold by Chinese retailers as "Fire Agate". But this labelling is absolutely wrong and misleading.
Natural Larimar in its most beautiful appearance
Picture: Jens Maier, Fa. Conlight
In 1974 a blue variety of the mineral pectolite (NaCa2[OH/Si3O8]) was discovered on the southwest coast of the Dominican Republic near Baoruco. Miguel Mendez, a local expert for arts and crafts products, coined the trade name »Larimar« because of the sea blue color of the stone ('mar' span. = sea) and in honor of his daughter Larissa.
When the »Larimar« deposits along the coast were exhausted, Mendez continued prospecting in the mountains further inland. At a distance of about seven kilometers from the coast he discovered a small primary deposit - so far the only known deposit of blue pectolite on earth.
Smoothly polished with a strong metallic lustere and magnetism strong enough to erase data on credit cards, a product called »Power Magnet« is sold on mineral faires since the beginning of the millenium. Children enjoy playing with the oval magnets for the incisive chirping noise created by tossing them in the air. But what is this highly magnetic material made of?
Some dealers suspected that the magnets may consist of sintered, neodymium doped Hematite. X-ray diffraction (XRD) analysis of a powdered sample carried out by the EPI laboratory revealed a different result: »Power Magnets« are manufactured from almost pure strontium ferrite mixed with some barium ferrite. Hematite or any other natural minerals have not been found.
»Power Magnets« are a well known artificial sinter product used in many industry goods that require permanent magnets (e.g. fridge doors). The correct denomination is: Power Magnets (artificial product).
Since the middle of the last century an Amber imitation has been on the market, produced by embedding real Amber chips into a transparent polyester resin. This imitation is called "Polybern". The name is derived from the contraction of "poly" from the word "polyester" and "bern" from the German "Bernstein" for Amber. For a long time this composition of fossil and synthetic resin had almost disappeared from the market, but now it is offered again in a slightly modified version. In this current product, transparent brown Amber chips are embedded into nontransparent white synthetic resin.
At the beginning of the new millenium, a colorful rock with the name »Rainbow Calsilica« appeared for the first time on mineral fairs. This rock is caracterisized by its striking layers of intensive blue, brown, white and green colors.
According to American and German studies this material was supposed to consist of microcrystalline calcite, deriving its colors from Allophane, a clay mineral. It was suspected that this rock had naturally formed as a crack filling in a volcanic rock (Rhyolite). But all of theses assumptions were wrong.
More accurate examinations by the EPI laboratory and other gemmological labs came to an entirely different conclusion. The mineral Allophane typically occurs in acid soils. Until now it has never been detected in solid rocks, since it decomposes immediately during petrogenetic processes. An X-ray diffraction (XRD) analysis showed that the blue, yellow and green strips solely contain calcite. However, since Allophane is amorphous in X-ray , supplementary methods of testing were required to detect the chromophoric substances.
