Abstract:
The traditional gem minerals of Sri Lanka usually take only the high quality gems
for selling and throw away the other remains. However, among these discarded
stones, low quality corundum, spinel, zircon, tourmaline, garnet etc. are present. The
aim of this research is to find out the areas which are abundant in such minerals, their
weight percentages in the washed gem bearing gravel in Ratnapura and Okkampitiya
gem fields and whether these minerals could be used for industrial and non-gem
ornamental purposes.
Samples were taken from selected locations in Ratnapura and Okkampitiya gem
fields. Minerals were identified by using there optical and physical properties,
determined their weight percentages in the washed gem bearing gravel and found out
economic uses of them.
The dispersion of the minerals in gem bearing gravel in Okkampitiya has a greater
uniformity compared to minerals in the Ratnapura gem field. Radioactive minerals are
abundant in residual and eluvial gem deposits compared to alluvial gem deposits.
Garnet, zircon, spinel and tourmaline are the common gem minerals in the Ratnapura
and Okkampitiya gem fields. Non gem quality minerals such as garnet, zircon, spinel
and tourmaline are found to be rich in all samples. However, iron rich minerals such
as magnetite, limonite, hematite etc. are found to be abundant in Rambuka,
Kahawatta, Marapana, Pothupitiya and Kuruvita areas. Gem miners are unaware of
uses for these minerals in industrial and non-gem ornamental purposes.
