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A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewelry or other adornments.
Gemstones of the World revised 5th edition, 2013 by Walter Schumann ISBN 978-1454909538 Smithsonian Handbook: Gemstones by Cally Hall, 2nd ed. 2002 ISBN 978-0789489852 hide
Bahia Emerald [2]; Carolina Emperor, [3] [4] 310 carats uncut, 64.8 carats cut; discovered in the United States in 2009, resides in the North Carolina Museum of Natural Sciences, Raleigh, NC, US
Lapis lazuli (UK: / ˌ l æ p ɪ s ˈ l æ z (j) ʊ l i, ˈ l æ ʒ ʊ-,-ˌ l i /; US: / ˈ l æ z (j) ə l i, ˈ l æ ʒ ə-,-ˌ l i /), or lapis for short, is a deep-blue metamorphic rock used as a semi-precious stone that has been prized since antiquity for its intense color.
Imperfections are unique for each emerald and can be used to identify a particular stone. Eye-clean stones of a vivid primary green hue (as described above), with no more than 15% of any secondary hue or combination (either blue or yellow) of a medium-dark tone, command the highest prices. [8]
Sapphire is a precious gemstone, a variety of the mineral corundum, consisting of aluminium oxide (α-Al 2 O 3) with trace amounts of elements such as iron, titanium, cobalt, lead, chromium, vanadium, magnesium, boron, and silicon.
After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions may indicate that the stone has been treated. Ruby is the traditional birthstone for July and is usually red/pinker than garnet , although some rhodolite garnets have a similar pinkish hue to most rubies.
The Oxford English Dictionary suggests an alteration of Anglo–Norman pedoretés (classical Latin pæderot-), a kind of opal, rather than the Arabic word faridat, meaning "gemstone". The Middle English Dictionary ' s entry on peridot includes several variations: peridod, peritot, pelidod and pilidod — other variants substitute y for letter i ...