“Hurlbutite,” 4 mm crystal pair on matrix, Chandlers Mill, Newport, NH. Photo courtesy of New Hampshire Mineral Species. Used with permission.
Hurlbutite is an extremely rare mineral. Minute, colorless faceted stones have been cut from fragments.
| Data | Value |
|---|---|
| Name | Hurlbutite |
| Colors | Colorless to greenish white; may be stained yellow. |
| Crystallography | Monoclinic; crystals prismatic, chunky, with etched surfaces and striations. |
| Refractive Index | 1.595-1.604 |
| Luster | Vitreous to greasy. |
| Hardness | 6 |
| Fracture | Conchoidal |
| Specific Gravity | 2.88. |
| Birefringence | 0.009 |
| Cleavage | None |
| Luminescence | None reported. |
| Luminescence Present | No |
| Transparency | Transparent to translucent. |
| Absorption Spectrum | Not diagnostic. |
| Formula |
CaBe2(PO4)2. |
| Pleochroism |
None.
|
| Optics |
a = 1.595; β = 1.601; γ = 1.604. Biaxial (-). |
| Optic Sign | Biaxial - |
| Etymology |
After Cornelius Hurlbut, well-known professor of mineralogy at Harvard University. |
| Occurrence |
In pegmatite with muscovite, albite, and other minerals. |
“Hurlbutite,” 3 cm crystal in pegmatite matrix, Chandlers Mill Mine, Newport, NH. Photo courtesy of New Hampshire Mineral Species. Used with permission.
To date, only hurlbutite from the type locality, Chandlers Mill, Newport, New Hampshire, has yielded clean, cuttable gem material. However, finding this seldom seen stone as a faceted gem would be quite unusual.
Strontiohurlbutite (SrBe2(PO4)2) is the strontium (Sr) analogue of the hurlbutite group. Hurlbutites are calcium (Ca) dominant. Both contain the rare element beryllium (Be).
Strontiohurlbutites have a light blue color, while hurlbutites range from white to greenish white.
In laboratories, scientists have created both hurlbutites and strontiohurlbutites for research purposes using a hydrothermal process. However, no jewelry use of these synthetics is known.
None known.
Gem-quality hurlbutites come from the Smith Mine, Chandlers Mill, Newport, New Hampshire.
Other sources include:
Fujian Province, China produces strontiohurlbutite.
Faceted gems, transparent and colorless, all fall under one carat in size.
You’re more likely to find hurlbutites, if at all, in comprehensive mineral collections than jewelry collections. With no cleavage and a hardness of 6, just below quartz, the small, transparent and colorless gems would make interesting conversation pieces if worn with care. (These conversations would likely dwell on their rarity). Consult our Gemstone Jewelry Cleaning Guide for more information.
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