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Sunday, June 19, 2011

Gemstone Occurrences in New Hampshire

Aquamarine crystals (beryl) that are like those found in pegmatite pockets in New Hampshire
Photo by Gery Perant


Amethyst is found throughout New Hampshire with locations listed for practically every county in the state as well as on the Isle of Shoals off the coast from Portsmouth.  It is listed in practically all the granite quarries found throughout the State.  Amethyst is a type of quartz having a purple coloring.  The stone was originally classified as a precious stone and was numbered among the crown jewels of France.

Beryl is the official mineral of New Hampshire that is found in the many pegmatites of western New Hampshire and other granitic rocks across the state where it is found as aquamarine and golden beryl.  On a fieldtrip held in conjunction with the Gilsum Mineral Show the author was also present when emerald crystals were found in biotite schist. These were emeralds that comparable in quality with those found at Crabtree Corners, North Carolina.

Amethyst crystals like those found in New Hampshire.
Photo by Rob Lavinsky

Corundum is a mineral that often occurs in granitic pegmatites as well as pellitic limestones although we were unable to find any site specific localities in New Hampshire it is apt to be found in any silica poor rocks.  There have been reports of rubies having been found in the state.  These reports are from the Moosilauke Lake region where it is found in marble.  Corundum is often associated with kyanite in schists. Other places in the state where corundum has been found include the Belknap Mountains and the area around Wakefield

Fluorite is calcium fluoride used primarily as flux in the steel making process that although it is too soft to be used as a regular gem is nonetheless faceted, cut into cabochons and used as a decorative stone under circumstances where it will not be subjected to wear and rough handling.  Fluorite can be found in southwestern New Hampshire around the town of Westmoreland where it was mined at one time for flux.  Today these old mines are a collector’s paradise with beautifully colored fluorite as well as several other minerals.

Since 1985 smoky quartz has been the state gemstone of New Hampshire where it is found throughout the state.  One of the best localities for collecting smoky quartz is located in the national forest just outside Conway where it is found in rotted granite in some aggregate quarries. 

The mineralogy collection at Harvard University contains over 200 specimens of topaz crystals that were collected on South Baldface Mountain in Chatham.  Topaz is a common rock forming mineral that is often mistaken for quartz.

Tourmaline is found in the many pegmatites of New Hampshire, and it was just over the border in Maine where the fabulous find was made at Newry Maine in 1972.  Pegmatites are found in many areas of the state, but are especially prevalent in Carroll and Grafton counties.  There is a feature called the Bronson Hill Anticlinorium that is thought to be the ancient island arc that is associated with the Taconic Orogeny of Western New England.

The best place to get information about gems and gemstones is from one of the many rock shops found throughout New Hampshire.

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