Agrellite ( Na Ca₂ Si₄ O₁₀ F) is a rare triclinic inosilicate

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

with four-periodic single chains of silica tetrahedra. It is a white to grey translucent mineral, with a pearly luster and white streak. It has a mohs hardness of 5.5 and a specific gravity of 2.8. Its type locality is the Kipawa Alkaline Complex,

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, where it occurs as tabular laths in pegmatite lenses. Other localities include Murmansk Oblast, Russia, Dara-i-Pioz Glacier, Tajikistan, and Saima Complex, Liaoning, China. Common associates at the type locality include Zircon, Eudialyte, Vlasovite, Miserite, Mosandrite-(Ce), and Calcite. Agrellite displays pink

fluorescence Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation. It is a form of luminescence. In most cases, the emitted light has a longer wavelength, and therefore a lower photon energy, tha ...

strongly under shortwave and weakly under longwave

ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...

. The fluorescent activator is dominantly Mn²⁺, with minor Eu²⁺, Sm³⁺, and Dy³⁺. It is named in honor of

Stuart Olof Agrell Stuart Olof Agrell (5 March 1913 – 29 January 1996) was an optical mineralogist and collaborator applying the electron microprobe to petrology. His involvement in the Apollo program brought him to the attention of the British media and public. ...

(1913–1996), a British mineralogist at Cambridge University.

References

Inosilicates Triclinic minerals Minerals in space group 2 {{silicate-mineral-stub