Pikes Peak Pebble Pups

Pikes Peak Pebble Pups

Saturday, March 12, 2011

Spessartine Garnet and Smoky Quartz: An Interesting Mineral Combination By Patrick Glover

The smoky quartz and spessartine garnet sample shown in figure 1 is about the size of your palm. The spessartine garnet is reddish-brown in color. The smoky quartz is a translucent crystal that ranges from a brown at the bottom of the crystal to black at the tip, and seems to sprout out of the ground mass of the specimen. This sample comes from the Wushan Spessartine mine in Tongbei, Yuxiao Co., Zhangzhou Prefecture, Fujian Province China. The Mine is in the southeastern edge of China (source: "Wushan spessartine mine" ).

Figure 1. Smoky quartz and spessartine garnet crystals.Both spessartine and smoky quartz are considered semi-precious gemstones. Note the striated faces on the spessartine crystal. The image is 2.5 cm across.  Photomicrograph © November, 2010 by Patrick Glover.
Spessartine garnet (magnesium aluminum silica) is a semi-precious gemstone (in this specimen it is translucent) and is found primarily in places such as Germany, Sri Lanka, China, and Brazil (source: The mineral and gemstone kingdom: spessartine). It was discovered in 1832. On the Mohs scale, spessartine has a hardness of 6.5-7.5. Spessartine has a specific gravity of 4.15 (Pellet, 1992). Spessartine is formed in manganese-rich metamorphic environments.

Smoky quartz (silica dioxide) forms in a variety of mineral environments and is found worldwide in places such as China, England, Scotland, and the United States (source: The mineral and gemstone kingdom: quartz). Smoky quartz is more common than spessartine, and was discovered in 300 BC. It has a hardness of 7 on the Mohs hardness scale and has a specific gravity of 2.65 (Pellet, 1992).

Both minerals are valuable as beads and talismans. The Egyptians made spessartine into beads and sold them as gems. The Scottish once believed that smoky quartz would heal the body (source: Folklore, legend, and healing properties).

The study specimen in this paper is one of the few samples imported from the southern edge of China. Other minerals imported from this area of China are helvite and topaz. This interesting combination of spessartine and smoky quartz crystals makes an attractive addition to a mineral collection.

References Cited:

Folklore, legend and healing properties. (n.d.). Retrieved from http://www.smokyquartzjewelry.com/

Pellett, Chris. (1999). Smithsonian handbooks: rocks and minerals. New York: DK Publishing.

The mineral and gemstone kingdom. (n.d.). Retrieved from http://www.minerals.net/mineral/spessartine.aspx

The mineral and gemstone kingdom: quartz. (n.d.). Retrieved from http://www.minerals.net/mineral/quartz.aspx

The mineral and gemstone kingdom: spessartine. (n.d.). Retrieved from http://www.minerals.net/mineral/spessartine.aspx

Wushan spessartine mine. (n.d.). Retrieved from http://www.mindat.org/loc-21240.html

Note: This article was written by Patrick Glover, a Junior (Pebble Pup) member for the Lake George Gem and Mineral Club. A modified APA reference style was used. © 2011, Patrick Glover. This article may be reprinted as long as author and home club is given credit.

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