corundum, ruby, sapphire, Sri Lanka.12, gems

Gem minerals from Embilipitiya and the Kataragama region of southern Sri Lanka are described through field observations, gemological measurements, microscopy, X-ray diffraction, and selected electron-microprobe analyses. Unlike the predominantly alluvial deposits around Ratnapura, both areas yield minerals from residual soils worked in shallow pits. Chemical corrosion is common, but the preservation of crystal faces, especially near Kataragama, indicates proximity to source rocks and contrasts with the rounded pebbles produced by prolonged transport. Embilipitiya is notable for substantial quantities of several unusual gem minerals, including orthopyroxene, cordierite, kornerupine, and reported scheelite, together with garnet and spinel. Nearly colorless orthopyroxene is identified as exceptionally magnesium-rich enstatite, with quartz inclusions and a strong ferrous-iron absorption line near 506 nm providing useful diagnostic evidence. Reddish brown orthopyroxene contains appreciably more iron and commonly exhibits liquid and two-phase inclusions. Nearly colorless cordierite has weak pleochroism, low refractive indices, and a magnesium-rich, iron-poor composition; its similarity to enstatite in appearance makes density and optical testing important. Kornerupine occurs abundantly as corroded or fractured material ranging from light brownish yellow to grayish green, with strong dichroism and variable iron contents. Its identification is supported by density, optical properties, and characteristic X-ray diffraction patterns. Unusually shaped quartz crystals resemble apophyllite because of strongly developed rhombohedral faces, while two purchased scheelites were reported to originate from Embilipitiya but were not confirmed by direct collection there. The Kataragama region contains more familiar gem assemblages, including sapphire and other corundum, spinel, almandine, hessonite, and brown tourmaline. Amarawewa spinels display well-developed octahedral faces and a strong absorption band near 549 nm. Scapolite contains marialite-rich inclusions interpreted as exsolution products, while hessonite from Tikiriyawewa contains numerous small transparent crystals that produce a granular appearance. Kochipadana yields relatively large corundum crystals, well-formed spinels, tourmaline, and less common apatite, titanite, actinolite, diopside, and green spodumene identified as hiddenite. The latter is characterized by strong dichroism, chromium absorption lines, a reddish Chelsea-filter reaction, and fluid inclusions. The account emphasizes the mineralogical diversity of these residual deposits, the diagnostic importance of combined testing, and the potential of Kochipadana as a source of sapphire, geuda, and additional gem-quality hiddenite.