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November-December 2017

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Topaz in New Hampshire's White Mountains

When one thinks of the mineral topaz, the first specimens that likely come to mind are those from Brazil, Russia, or Utah, but good crystals are now also coming from China, Pakistan, and several other localities throughout the world. New Hampshire, however, has produced topaz crystals for more than 125 years and is often overlooked as a producer of excellent specimens from miarolitic cavities in dominantly niobium-yttrium-fluorine (NYF)-type granite pegmatites (Rakovan 2008).

New Hampshire is a heavily forested state, making specimen discovery difficult even when outcrops are found. The granite is very tenacious, and because occurrences are in a National Forest, only hand tools can be used to get to the cavities in which the topaz occurs. The state was not so heavily forested in the eighteenth and nineteenth centuries due to farming and extensive logging for ship masts, building materials, and fuel. However, the mountain localities in which the miaroles occur were not extensively logged, so localities were difficult to find for many years. In the late 1800s and early 1900s, huge forest fires on many New Hampshire mountains laid bare large areas, including South Baldface Mountain and Greens Ledge in particular, which temporarily opened up areas for prospecting. The ash layer is still evident when digging through the soil in these areas. It did not take long for the forest and topsoil to reclaim the ledges, and today only 15–20 percent of the bare ledges remain. Despite this, a small but steady production of topaz has continued through the years from the efforts of many field collectors. The meager output will likely continue as long as there are collectors willing to work hard for the prize of a fine topaz crystal. 

 

Donald Dallaire has been collecting minerals since 1971 and specializes in apatite and New Hampshire minerals. He is on the board of trustees of the Maine Mineral & Gem Museum.

James Nizamoff has a master's degree in geology from the University of New Orleans and specializes in pegmatite mineralogy. He is a member of the “MP2” research group associated with the Maine Mineral & Gem Museum.

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