Mineral Gallery
Gold Nugget
Written by Boss Tambang Tuesday, 01 December 2009 23:54
This close-up shows a gold nugget about eight times enlarged. It came from an Alaskan streambed, where its edges were smoothed by hundreds of years of pounding among the cobbles. Native gold is usually alloyed with some copper as well as other noble metals like silver, platinum, and palladium. It rarely accumulates into pieces this big. When it’s visible...
Halite
Written by Boss Tambang Tuesday, 01 December 2009 23:51
Halite is natural rock salt. Whenever seawater evaporates, several different minerals come out of solution, starting with the carbonate mineral calcite, then gypsum, then halite. In places where evaporation happens repeatedly, halite beds can be 1,000 meters thick. Halite is a soft mineral that flows easily under pressure. At depths of as little...
“Herkimer Diamond” Quartz Crystal
Written by Boss Tambang Tuesday, 01 December 2009 23:49
The Cambrian limestones near the town of Herkimer, New York, yield distinctive doubly terminated quartz crystals known as “Herkimer diamonds.” This is a specimen I dug up at the Herkimer Diamond mine some thirty years ago, enlarged about 2.5 times. The first view, with a dark background, shows the play of colors. The second, with...
Magnetite
Written by Boss Tambang Tuesday, 01 December 2009 23:48
Magnetite is a common iron oxide mineral, named for an ancient region of Greece where metal production was prominent. It is the only mineral that exhibits strong magnetism, although others like ilmenite and hematite have weakly magnetic behavior. Most magnetite occurs in very small grains. When a...
Muscovite
Written by Boss Tambang Tuesday, 01 December 2009 23:46
Muscovite is the most common mica mineral. It’s also called white mica. The best way to tell a mica is by the thin, transparent sheets that it cleaves into. Large, clear plates of mica were once commonly used for windows, and the productive Russian mica mines giave muscovite its name. Today mica windows are still used in...
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