CHALCOPYRITE GALENA QUARTZ
An outstanding specimen with Chalcopyrite Galena Quartz and Sphalerite. Terminated Quartz, with chunky Galena crystals topped by large Chalcopyrite crystals and with Sphalerite on top. What an amazing combo showing large chunks of well formed crystals with great colour contrast. A very collectible specimen.
Krushev Dol Mine, Madan, Bulgaria.
9cm x 8cm x 9cm, 1086g.
A major ore of copper. Common in sulfide veins and disseminated in igneous rocks.
Weathering may lead to the formation of malachite, azurite, brochantite, langite and numerous other secondary copper minerals.
Quartz, Silicon Dioxide:
One of the most common minerals found in the Earth’s crust. If pure, quartz forms colourless, transparent and very hard crystals with a glass-like luster. Quartz is a significant component of many igneous, metamorphic and sedimentary rocks. Silicon dioxide is found in a wide range of varieties and colours. Quartz in its polished form, was the most advanced technology thousands of years ago.
Galena is a common and popular mineral for rock hounds. Its characteristic cubes, distinctive cleavage and high density make it easy to identify. The structure of Galena is identical to that of halite, NaCl. The two minerals have the same crystal shapes, symmetry and cleavage. Some Galena may contain up to 20% silver in place of lead.
One of the first transistors was a Galena Crystal and with a copper wire called “cats-whisker-with crystal”. Galena is a natural semiconductor. Really it formed part of a transistor, a more reliable PN junction or Diode. Metal Sulfides form natural PN Junctions like copper and copper oxide which also formed one of the first solar panels. Such an interesting subject I could on on about it.
Sphalerite also known as Blende or Zinc Blende is the major ore of zinc. When pure with little or no iron it forms clear crystals with colours ranging from pale yellow (Cleiophane) to orange and red shades (Ruby Blende). As the iron content increases it forms dark, opaque metallic crystals of Marmatite.