After the American geologist, Josiah Edward Spurr (1870-1950).
Occurrence
A contact mineral in limestones.
Inclusions
Black magnetite crystals
Purplish spurrite and white hillebrandite crystals on matrix, 2.5 x 1 x 0.5 cm, Fuka Mine, Bicchu-cho, Takahashi City, Okayama Prefecture, Japan. Photo courtesy of liveauctioneers.com and Jasper52.
Comments
In 1986, polished slabs of spurrite as well as rough material appeared in substantial quantities at a mineral show. This translucent to opaque material from Mexico had medium to dark purple colors. Since then, other sources have been discovered, but the material is still rarely encountered in the gem trade. The pieces lapidaries do work usually become cabs, beads, and decorative items. Faceted spurrites are extremely rare.
When tested in gem labs, spurrites have shown some variation in their fluorescence. Some stones have shown green cathodoluminescence under a beam of electrons as well as green luminescence under shortwave (SW) ultraviolet (UV) light.
Others spurrites have shown different results. In 2004, the GIA tested a specimen that proved inert under SW UV but showed light blue luminescence under longwave (LW) UV. Other specimens examined showed pinkish-orange and orange cathodoluminescence. Since these specimens were aggregate minerals, the researchers speculated that some of the components in the specimens could have affected their cathodoluminescence.
The best known sources for gem material are the Velardeña mining district, Durango, Mexico and Okayama Prefecture, Japan.
Other notable sources include the following:
United States: Crestmore, California; Luna County, Tres Hermanas, New Mexico.
United Kingdom: Scawt Hill, County Antrim, Northern Ireland; Scotland.
Israel; New Zealand; Russia; Turkey.
Spurrite, Luna County, New Mexico. Photo by David Dyet. Public Domain.
Care
You’re more likely to find a spurrite in a mineral collection, if at all, than a jewelry collection.
With a hardness of 5 and distinct cleavage, any cut spurrites should receive protective settings in rings. Other jewelry use, such as necklaces or brooches, should pose no exceptional risks to these stones. However, resist the temptation to just wipe dust and grit off these gems or decorative objects. Spurrites have a lower hardness than household dust (7), which will scratch them. Wash these pieces with a soft brush, mild detergent, and warm water.