The Herkimer Diamond is not actually a diamond, but is a double ended quartz crystal found in open dolostone outcrops in and around Herkimer County, New York and the Mohawk River Basin. The "diamond" in their name is due to both their clarity and natural faceting - the crystal has double termination point and 18 total faces (six at each point, six around the center). Because the first discovery spots are in the village of Middleville and in the town of Little Falls, respectively, the crystal is also known as the diamond Middleville or the diamond Little Falls .
The Herkimer diamond became widely known after the workers found them in large numbers while cutting into the dolphin of the Mohawk River at the end of the 18th century. Geologists find exposed dolostone in Herkimer County outcroppings and start to mine there, leading to the "Herkimer diamond" moniker. Double point quartz crystals can be found on sites around the world, but only mined in Herkimer County can be named this.
The history of this crystal geology began about 500 million years ago in the shallow seas that received sediment from the ancient Adirondak Mountains to the north. The calcium and magnesium carbonate accumulated and lithified sediments to form dolostone bedrocks are exposed as Little Falls Dolostone today. When buried, the cavity is formed by acidic water forming a hole in which a quartz crystal is formed. While the dolostone unit is Cambrian in quartz age in interpreted vistas have been formed during the Carboniferous Period. Organic wax, silicon dioxide and pyrite (iron sulfide) materials present as minor constituents of rocks made of dolomite and calcite. When the sediment buries the rock and the temperature rises, the crystals grow inside the cavity very slowly, producing quartz crystals with remarkable clarity. Inclusions can be found in crystals that give clues to the origin of the Herkimer diamond. Found in inclusion are solids, liquids (brine or petroleum), gases (most often carbon dioxide), inclusions of two and three phases, and negative (uniaxial) crystals. Anthraconite is the most common solid inclusion.
Video Herkimer diamond
References
Maps Herkimer diamond
External links
- Website for New York State Minerality Academy
- Prospecting for Herkimer Diamonds
- HerkimerHistory.com
- Video mining for Herkimer Diamonds with jackhammer
- Book Review: Collector's Guide for Herkimer Diamonds
Source of the article : Wikipedia
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