Archives for the month of: September, 2011

Grandidierite, named after the French explorer Alfred Grandidier, is one of the all time classics in the rare gemstone market. It is virtually impossible to find clear gems and collectors are happy to get mineral quality gems. A classic location in the jungle of Madagascar is “lost” and it is unlikely that it ever will be rediscovered again. Find grandidierites at www.freakingcat.com

 

 

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A rare, big sized, 14.56 cts, bright red Polyhalite, which easily dissolves in water. Polyhalite is an evaporite mineral, a hydrated sulfate of potassium, calcium and magnesium with formula: K2Ca2Mg(SO4)4·2(H2O). Polyhalite crystallizes in the triclinic system although crystals are very rare. The normal habit is massive to fibrous. It is typically colorless, white to gray, although it may be brick red due to iron oxide inclusions. It has a Mohs hardness of 3.5 and a specific gravity of 2.8 – Find it at www.freakingcat.com

 

 

 

 

 

 

Anatase is one of the three (mindat says 5) mineral forms of titanium dioxide, the other two being brookite and rutile. Very hard to find eyeclean specimen, which are stunning when facetted. Find more rare collector stones at www.freakingcat.com

 

 

 

 

Apache tears are rounded nodules of obsidian (volcanic black glass) with diameter from about 0.5 to 5 cm. An Apache tear looks opaque by reflected light, but translucent when held up to light. Apache tears are usually black, but can range from black to red to brown. They are often found embedded in a greyish-white perlite matrix

The name “Apache tear” comes from a legend of the Apache tribe: about 75 Apaches and the US Cavalry fought on a mountain overlooking what is now Superior, Arizona in the 1870s. Facing defeat, the outnumbered Apache warriors rode their horses off the mountain to their deaths rather than be killed. The wives and families of the warriors cried when they heard of the tragedy; their tears turned into stone on hitting the ground. Find more rare collector gemstones at www.freakingcat.com

Apache tears

Apache tears

 

 

 

 

 

Spherocobaltite (or Cobalto Calcite) is a manganese carbonate mineral with chemical composition CoCO3. In its (rare) pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. Find more rare collector gemstones at www.freakingcat.com

 

 

Sphaerocobaltite Freakingcat

Sphaerocobaltite

Laumontite is a mineral of the zeolite group. Laumontite easily dehydrates when stored in a low humidity environment. When freshly collected, if it has not already been exposed to the environment, it can be translucent or transparent. Over a period of hours to days the loss of water turns it opaque white. In the past, this variety has been called leonhardite, though this is not a valid mineral species. The dehydrated laumontite is very friable, often falling into a powder at the slightest touch. Best keep it hydrated folks! Find more rare collector gemstones at www.freakingcat.com

Laumontite, Freakingcat

Freakingcat Laumontite

 

 

 

 

 

Narsarsukite – Named after the original location in Greenland, but it can also be found in Canada, Mount St. Hillaire. It comes in green or even more rare in yellow and is usually embedded in rock. It’s a challenge to cut out this material from the rough rock and facet it. Find more rare collector gemstones at www.freakingcat.com

Formed over 3.000.000.000 years ago. Nuumite is found in an area slightly north of Nuuk, Greenland – accessible only by boat. The area where Nuumite occurs is in the so-called ‘Isuakasia’ iron ore region, the origin of which dates back almost four billion years. Nuumite has been used rather widely for untold centuries as beads and ornamental stones. The locality is high in the mountains and requires lugging heavy mining equipment up to retrieve the best specimens. These areas produce some of the oldest stones found on earth, and Nuumite falls in this category. Geologically speaking, nuumite is of volcanic origin and was formed about 3 billion years ago. Subsequent influences on the rock (metamorphism) have given rise to the striking mixture of crystals which gives Nuumite its unique appearance. Rocks resembling nuumite are also found in a few minor occurrences in the USA, but it is only in the Greenland type that colouration is developed well enough for the stone to be suitable for gemstones.

At first glance, Nuumite appears similar to labradorite but upon closer examination the beauty of nuumite and its schiller effect is astonishing. Labradorite usually shows broad splotches of “flash” while the smaller mixture of elongated crystals in nuumite (often in sheaf-like groups) create a striking gemstone. In the transition between the individual crystals (and especially the thin ones), an optical effect is created causing a special “inner” golden brown glow. This effect is also called iridescence, and is especially distinct on polished surfaces. The result is that the crystals appear as bright lamellae, almost like flames in a fire. The colours vary somewhat between reddish, greenish, and bluish hues, sometimes even within the same lamella. Between the bright lamellae, the colour is dark brown to black. Find more rare collector gemstones at www.freakingcat.com

Nuumite - Freakingcat, rare gemstone

Nuumite - Freakingcat, rare gemstone