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Asterism on the surface of a blue star sapphire. A purple-pink star sapphire displaying asterism in a platinum ring.. An asterism (from Ancient Greek ἀστήρ (astḗr) 'star' and -ism) is a star-shaped concentration of light reflected or refracted from a gemstone.
Sapphires are a precious gemstone, a variety of the mineral corundum, consisting of aluminum oxide (α-Al 2 O 3) with trace amounts of elements such as iron, titanium, chromium, copper, or magnesium. It is typically blue, but natural "fancy" sapphires also occur in yellow, purple, orange, and green colors; "parti sapphires" show two or more colors.
Gold models of ship and cauldron, torc, from the Broighter Hoard. The list of hoards in Ireland comprises the significant archaeological hoards of coins, jewellery, metal objects, scrap metal and other valuable items that have been discovered on the island of Ireland (Republic of Ireland and Northern Ireland).
Padparadscha sapphires are rare; the rarest of all is the totally natural variety, with no sign of artificial treatment. [12] The name is derived from the Sanskrit padma ranga (padma = lotus; ranga = color), a color akin to the lotus flower (Nelumbo nucifera). [13] Among the fancy (non-blue) sapphires, natural padparadscha fetch the highest prices.
The five cardinal gems. Clockwise from top: sapphire, ruby, emerald, amethyst, diamond. Cardinal gems are gemstones which have traditionally been considered precious above all others. The classification of the cardinal gems dates back to antiquity, and was largely determined by ceremonial or religious use as well as rarity. [1]
The 2nd-century Alexandrian Greek writer Ptolemy, one of the most important geographers, mathematicians and astronomers in the ancient world, refers to Ireland in two of his works. In the astronomical treatise known as the Almagest he gives the latitudes of an island he calls Mikra Brettania (Μικρὰ Βρεττανία) or "Little Britain ...
This is a list of gemstones, organized by species and types. Minerals. There are over 300 types of minerals that have been used as gemstones. Such as: A–B
Coin of King "Sihtric" of Dublin (r. 989–1036– ) Hiberno-Norse coins were first produced in Dublin in about 997 under the authority of King Sitric Silkbeard.The first coins were local copies of the issues of Aethelred II of England, and as the Anglo-Saxon coinage of the period changed its design every six years, the coinage of Sitric followed this pattern.