Ashcroftine-(Y) is a rare, hydrous, yttrium-bearing inosilicate mineral containing potassium, sodium, and calcium, together with hydroxide and carbonate anions. Its idealized chemical formula is . It was named after the British mineral collector Frederick Noel Ashcroft (1878–1949), a benefactor of the British Museum (Natural History).
Description Ashcroftine-(Y) crystallizes in the tetragonal crystal system. It is generally pale pink and transparent to translucent, with a measured specific gravity of 2.61. Its crystals are typically needle-like or fibrous and may occur as fine intergrowths, divergent sprays, or radial-fibrous and matted-fibrous aggregates. Its cleavage is perfect on {100} and distinct on {001}.
Occurrence The type locality is the Narssârssuk pegmatite in southern Greenland, where ashcroftine-(Y) occurs in cavities in alkaline syenite. It has also been found in igneous breccia and pegmatites of the intrusive alkaline gabbro–syenite complex at the Poudrette quarry, Mont Saint-Hilaire, Quebec, Canada, and at Cava dell'Osa, near Rome, Lazio, Italy.
Kola ashcroftine phase A study published on 7 May 2026 described a previously collected, ashcroftine-related mineral phase from the Kirovsky mine in the Khibiny alkaline massif on the Kola Peninsula, Russia. The phase, designated KA, has the idealized formula . It contains calcium, manganese, and fluorine, and its crystal structure includes silicate nanotubules.
See also List of minerals named after people
References
External links
Ashcroftine-(Y) mineral data at Webmineral Ashcroftine-(Y) in the Handbook of Mineralogy