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In these cases, halite is said to be behaving like a rheid. Unusual, purple, fibrous vein-filling halite is found in France and a few other localities. Halite crystals termed hopper crystals appear to be "skeletons" of the typical cubes, with the edges present and stairstep depressions on, or rather in, each crystal face. In a rapidly ...
Traditional Gem Fields of Sri Lanka. Sri Lanka ’s gem industry has a very long and colorful history. Sri Lanka was affectionately known as Ratna-Dweepa which means Gem Island. The name is a reflection of its natural wealth. Marco Polo wrote that the island had the best sapphires, topazes, amethysts, and other gems in the world. [1]
Sinhalite. Grains, rolled pebbles, irregular masses. Rarely euhedral crystals. Sinhalite is a borate mineral with formula MgAl (BO 4 ). [ 2] Sinhalite was first found in Sri Lanka (Ceylon) in 1952, and was named from Sinhala - the Sanskrit name for Sri Lanka. [ 3] Gemstone quality Sinhalite can also be found in Madagascar, Tanzania and Myanmar ...
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. Minerals occurring with serendibite include ...
The Minerals Portal. In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form. The geological definition of mineral normally excludes compounds that occur only in living organisms.
Apatite is a group of phosphate minerals, usually hydroxyapatite, fluorapatite and chlorapatite, with high concentrations of OH −, F − and Cl − ion, respectively, in the crystal. The formula of the admixture of the three most common endmembers is written as Ca 10 (PO 4) 6 (OH,F,Cl) 2, and the crystal unit cell formulae of the individual ...
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. Clear and well-colored stones are rare as the radioactivity tends to degrade the crystal matrix over time in a process known as metamictization .
Cleavage (crystal) Cleavage, in mineralogy and materials science, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the ...