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Ninety percent of the rocks of the island are of Precambrian age, 560 million to 2,400 million years ago. The gems form in sedimentary residual gem deposits, eluvial deposits, metamorphic deposits, skarn and calcium-rich rocks. Nearly all the gem formations in Sri Lanka are located in the central high-grade metamorphic terrain of the Highland ...
More than 90% of Sri Lanka's surface lies on Precambrian strata, some of it dating back 2 billion years. [6] The granulite facies rocks of the Highland Series (gneisses, sillimanite-graphite gneisses, quartzite, marbles, and some charnockites) make up most of the island and the amphibolite facies gneisses, granites, and granitic gneisses of the Vijayan Series occur in the eastern and ...
Ekanite is an uncommon silicate mineral with chemical formula Ca 2 ThSi 8 O 20 or (Ca,Fe,Pb) 2 (Th,U)Si 8 O 20. It is a member of the steacyite group. It is among the few gemstones that are naturally radioactive. Most ekanite is mined in Sri Lanka, although deposits also occur in Russia and North America.
Taaffeite occurs in carbonate rocks alongside fluorite, mica, spinel and tourmaline. This extremely rare mineral is increasingly found in alluvial deposits in Sri Lanka [11] and southern Tanzania, [2] as well as lower grade taaffeite in limestone sediments in China. [9]
In mineralogy, an inclusion is any material trapped inside a mineral during its formation. In gemology , it is an object enclosed within a gemstone or reaching its surface from the interior. [ 1 ] According to James Hutton 's law of inclusions, fragments included in a host rock are older than the host rock itself.
In India he raised an army with the intention of returning and retaking the throne of Sri Lanka, which he considered to be rightfully his. Expecting the inevitable return of Moggallana, Kashyapa is said to have built his palace on the summit of Sigiriya as a fortress as well as a pleasure palace.
Thorianite is a rare thorium oxide mineral, ThO 2. [5] It was originally described by Ananda Coomaraswamy in 1904 as uraninite, [ 6 ] but recognized as a new species by Wyndham R. Dunstan . [ 7 ] It was so named by Dunstan on account of its high percentage of thorium ; it also contains the oxides of uranium , lanthanum , cerium , praseodymium ...
Serendibite is an extremely rare silicate mineral that was first discovered in 1902 in Sri Lanka by Dunil Palitha Gunasekera and named after Serendib, the old Arabic name for Sri Lanka. The mineral is found in skarns associated with boron metasomatism of carbonate rocks where intruded by granite.