. "Sinkankasite"@en . "Sinkankasite, mineral formula: H2MnAl(PO4)2(OH)\u00B76H2O, was named after John Sinkankas (1915\u20132002), noted author and mineral collector, Scripps Institute of Oceanography. It is triclinic; as colorless, bladed to prismatic crystals up to 4 mm in length, often as divergent, radial aggregates and as pseudomorphs after triphlyte crystals; occurs in the Barker pegmatite (formerly Ferguson pegmatite), east of Keystone, South Dakota, and in the Palermo pegmatite, North Groton, New Hampshire."@en . .