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Southwest Sunset

Ametrine and rose quartz carving by Sherris Cottier Shank
Photo by Sherris Cottier Shank. Click to zoom.
Catalog Number NMNH G11509-00
Locality Bolivia
Weight 442.9 ct

Gift of Ms. Sherris C. Shank in 2015.

The “Southwest Sunset” is an ametrine and rose quartz sculpture created by award-winning gem artist Sherris Cottier Shank. In 1999, Shank was driving from Phoenix to Tucson, Arizona and was inspired by a magnificent sunset. The idea was to use the deeply saturated golden-purple ametrine as a setting sun. This natural ametrine is from Bolivia and exhibits the golden-yellow to purple bi-color seen in fine quality material. She later decided to use light pink rose quartz to represent the clouds. To find large, clean, gem-quality crystals of any gem material is extremely difficult. To end up with a finished ametrine gem that weighs over 443ct, the original crystal had to weigh approximately 1200ct, as the loss of material from cutting and carving is extremely high. Shank used a very fine translucent piece of rose quartz with strong color to express the softness of the clouds and gave it a matte finish to contrast with the polished ametrine sun. Again, a very large piece of rough was needed to end up with a rose quartz base of over 1400ct. This rose quartz is exceptionally fine in clarity, transparency, and color, as most rose quartz appears turbid and opaque. To transform the rough into gems, Shank’s attention to detail was crucial in every aspect, from selecting the gem material, to imagining the design, pre-forming the rough, refining the shape, sculpting the details, and then sanding and polishing the gem to completion. Carving “Southwest Sunset” took Shank a solid month. The sculpture, which evokes the blazing sunsets of the American Southwest, is 2.75” tall and 4” wide. Quartz is one of the most abundant minerals in the Earth’s crust. It is composed of the elements silicon and oxygen, and in its pure state is colorless. However, small amounts of various impurity atoms can yield a wide range of colors. The translucent to opaque pink variety of quartz is called rose quartz. Amethyst, the most prized gem variety of quartz, is purple. Citrine is the golden-yellow to orange variety of quartz. And gems that are part amethyst and part citrine (bi-color) are known in the trade as ametrine. The color zoning in ametrine is due to differing oxidation states of iron inside the crystal. The most significant source of ametrine is from the Anahi Mine in eastern Bolivia. It is the only mine known where commercial quantities of naturally occurring ametrine are found. However, there are deposits in Brazil and India, but most of this ametrine is artificially created by the heat treatment and/or radiation of amethyst. The ametrine and rose quartz in the Southwest Sunset sculpture are natural and have had no enhancements.


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