gems, corundum, Sri Lanka.12, garnet, zircon, spinel, tourmaline, sillimanite

Reports twelve mineralogical observations from Ceylon (Sri Lanka), combining field occurrences, crystallographic descriptions, and chemical analyses. The principal section discusses newly identified thorianite from Bambarabotuwa, its distinction from uraninite, radioactivity, helium content, associated minerals, and potential commercial importance. Other notes describe corundum–sillimanite rocks at Haldummulla, phlogopite near Kandy, kyanite in offshore sands, and replacement of limestone by chert and opal. Further observations cover talc, stilbite, serendibite, moonstone, kaolin, sphene, and arsenopyrite. Of particular gemological interest are the corundum-bearing rocks, an additional serendibite locality, and analysis of sodium-rich orthoclase moonstone from Gangapitiya.