| front |
back |
revisions |
lasted changed by |
history |
| Dispersion |
-separation of white light into a rainbow of colors |
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johnwp06 Wed, 17 Mar 2010 03:27:00 GMT |
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| color center |
structural imperfections in cyrstals causing selective absorption of light. |
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johnwp06 Wed, 17 Mar 2010 03:01:08 GMT |
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| labradorescence |
phenomena - mettalic hues on gemstone (mainly labradorite) |
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johnwp06 Sun, 14 Mar 2010 23:55:12 GMT |
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| adularescence |
phenomena -
blue/white inclusions that glow; present in moonstones |
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johnwp06 Sun, 14 Mar 2010 23:54:39 GMT |
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| chatoyancy |
phenomena -
cat's eye |
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johnwp06 Sun, 14 Mar 2010 23:54:39 GMT |
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| opalescence |
phenomena -
light diffraction in opal |
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johnwp06 Sun, 14 Mar 2010 23:54:39 GMT |
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| orient |
phenomena -
rainbow-like colors in pearls |
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johnwp06 Sun, 14 Mar 2010 23:54:39 GMT |
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| Monoclinic Crystal System |
Crystal System of:
-Jade |
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johnwp06 Sun, 14 Mar 2010 23:43:34 GMT |
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| Orthorhombic System |
Crystal System of:
-Pearl
-Chrysoberyl
-Olivine |
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johnwp06 Sun, 14 Mar 2010 23:43:34 GMT |
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Hexagonal System
w/
Ring Silicates |
Crystal Sytem of:
-Beryl |
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johnwp06 Sun, 14 Mar 2010 23:43:34 GMT |
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| Hexagonal System |
Crystal System of:
-Corundum
-Tourmaline
-Quartz
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johnwp06 Mon, 15 Mar 2010 00:05:59 GMT |
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| Cubic System |
Diamonds' Crystal System
Garnet's Crystal System
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johnwp06 Sun, 14 Mar 2010 23:43:27 GMT |
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| Biomineralization |
the formation of a gem-mineral by a living organism |
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johnwp06 Sun, 14 Mar 2010 23:31:09 GMT |
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| Fancy Gems |
-"colored gems" |
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johnwp06 Sun, 14 Mar 2010 23:31:09 GMT |
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| Adamanitine |
-diamond like luster |
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johnwp06 Mon, 15 Mar 2010 00:18:35 GMT |
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| Dates to Know |
•1725 – diamonds discovered in New World
•1792 – French Revolution, Hope Diamond stolen
•1812 – Hope Diamond (French Blue) resurfaces and is sold; after 20 years an object stolen from France is no longer France’s property.
•1859 – diamonds first discovered in South Africa
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johnwp06 Mon, 15 Mar 2010 00:07:44 GMT |
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| 3 Types of Industrial Diamonds |
-what type of diamonds?
- bort - poorly crystalized
- ballas - spherical, small
- carbonado - meteorite diamonds |
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johnwp06 Fri, 12 Mar 2010 02:35:57 GMT |
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| Central Selling Org. (CSO) |
-group of diamond producers that cooperatively sell diamonds
-controls 60-80% of world’s diamond legal trade |
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johnwp06 Fri, 12 Mar 2010 02:31:54 GMT |
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| Cecil Rhodes |
– S. Africa, 1870; bought claim in Da Beers mine
-Formed Da Beers Mining Co. Ltd.
-Limited sales of diamonds to stabilize prices
-1890; Elected prime minister of S. Africa |
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johnwp06 Fri, 12 Mar 2010 02:31:54 GMT |
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| Idiochromatic |
– “self-colored,” color-causing elements are essential to chemical composition of stone (ex: Corundum – ruby) |
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johnwp06 Fri, 12 Mar 2010 02:31:53 GMT |
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| Allochromatic |
- "colored,” gems colorless when pure; color produced by impurities |
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johnwp06 Fri, 12 Mar 2010 02:31:53 GMT |
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| Pleochroism |
-color change of minerals at different angles |
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johnwp06 Fri, 12 Mar 2010 02:29:38 GMT |
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| Streak |
-color of a powdered mineral |
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johnwp06 Fri, 12 Mar 2010 02:29:38 GMT |
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| Fracture vs. Cleavage |
Fracture - breakage on surface
Cleavage - breakage on weak planes |
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johnwp06 Fri, 12 Mar 2010 02:29:38 GMT |
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| Polymorphs |
-having the same chemical compositions but diff. crystal structure (diamonds and graphite) |
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johnwp06 Fri, 12 Mar 2010 02:29:38 GMT |
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| Van der Waals Bond |
-weakest bond
-present on cleavage planes |
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johnwp06 Fri, 12 Mar 2010 02:25:23 GMT |
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| Ionic Bond |
-Weak type of chemical bond |
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johnwp06 Sat, 13 Mar 2010 16:27:32 GMT |
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| Covalent Bond |
-strongest type of chemical bond |
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johnwp06 Fri, 12 Mar 2010 02:25:23 GMT |
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| Phosphorescence |
- energy absorbed by a substance is released; “glow-in-the-dark” |
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johnwp06 Fri, 12 Mar 2010 02:25:23 GMT |
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| Fluorescence |
– glow exuded by diamonds or other gemstones when exposed to ultraviolet light |
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johnwp06 Fri, 12 Mar 2010 02:23:34 GMT |
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| Amorphous |
-a class of gems that does not have a crystalline structure
(ex: glass, amber, opal) |
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johnwp06 Sun, 14 Mar 2010 23:57:02 GMT |
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| Crystal |
-a solid having a regular internal arrangement of atoms or ions, with flat surfaces |
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johnwp06 Fri, 12 Mar 2010 02:23:33 GMT |
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| Metamorphic Environments |
-gemstone environment
-rocks changed by heat/pressure |
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johnwp06 Fri, 12 Mar 2010 02:23:33 GMT |
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| Igneous Environments |
-gemstone environment
-magma/molten rocks |
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johnwp06 Fri, 12 Mar 2010 02:21:50 GMT |
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| 4 C's |
-Cut – ideal proportions for a gem; optimize brilliance and fire to increase value of gem
-Color – some colors more desirable than others (blue = most desirable)
-Clarity – flaws decrease value (cracks, inclusions)
-Carat Weight – larger stone = greater value |
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johnwp06 Fri, 12 Mar 2010 02:21:50 GMT |
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| Stability |
-resistance to color loss due to heat, light or chemicals |
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johnwp06 Fri, 12 Mar 2010 02:21:50 GMT |
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| Toughness |
-resistance to chipping/fracturing |
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johnwp06 Fri, 12 Mar 2010 02:21:50 GMT |
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| Moh's Hardness Scale |
-1 – Talc
-2 – Gypsum
-3 – Calcite
-4 – Fluorite
-5 – Apatite
-6 – Feldspar/Orthoclase
-7 – Quartz
-8 – Topaz
-9 – Corundum (Sapphires)
-10 – Diamond (Carbon) |
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johnwp06 Fri, 12 Mar 2010 02:19:15 GMT |
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| Durability/Hardness |
-resistance to scratching |
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johnwp06 Fri, 12 Mar 2010 02:19:15 GMT |
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| Critical Angle |
-angle at which total internal reflection is achieved |
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johnwp06 Fri, 12 Mar 2010 02:19:15 GMT |
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| Refraction |
-bending of light as it passes from air to gem |
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johnwp06 Fri, 12 Mar 2010 02:19:15 GMT |
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| Reflection |
- bouncing of light off a facet |
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johnwp06 Fri, 12 Mar 2010 02:17:33 GMT |
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| 5 Facets of a Gemstone |
-Table – top facet, largest, flat surface on top of stone
-Crown – top of stone (upside down it looks like a crown)
-Girdle – edge between crown and pavillon
-Pavillon – lower part of stone
-Culet – small facet on bottom of stone, made to decrease likelihood of fracture when dropped |
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johnwp06 Fri, 12 Mar 2010 02:17:33 GMT |
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| Facet |
-a flat, polished surface of a gemstone |
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johnwp06 Fri, 12 Mar 2010 02:17:33 GMT |
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| Luster |
-appearance of light as it reflects off the surface of a gem. |
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johnwp06 Fri, 12 Mar 2010 02:17:33 GMT |
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| Fire |
-rainbow-like flashes of color in gems |
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johnwp06 Fri, 12 Mar 2010 02:15:40 GMT |
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| Brilliance |
-amt of sparkle a gemstone has |
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johnwp06 Fri, 12 Mar 2010 02:15:40 GMT |
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| Beauty |
key attribute of a gemstone |
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johnwp06 Fri, 12 Mar 2010 02:15:40 GMT |
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| Gem |
-material that is sufficiently durable and attractive to be used for personal adornment |
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johnwp06 Fri, 12 Mar 2010 02:15:40 GMT |
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| Ammolite |
oAragonite shell of cretaceous ammonite cephalopods
Relatives of the modern nautilus
Shell still has mother of pearl layer |
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johnwp06 Fri, 12 Mar 2010 02:11:38 GMT |
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| Fossil |
-evidence of ancient life; at least 11,800 yrs old |
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johnwp06 Fri, 12 Mar 2010 02:11:38 GMT |
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| Jet |
•Origin: bituminous coal; sedimentary deposits, worldwide, mostly from England.
•Origin of name: from old French, jaiet
•Composition: carbon
•Streak – black |
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johnwp06 Fri, 12 Mar 2010 02:11:38 GMT |
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| Coral |
•Origin – skeletons of marine corals; tropical seas
•Composition – aragonite
•Hardness: 3-4
•Colors – various
•Streak – white
•Luster – vitreous (when polished)
•Fluorescence – weak, violet. |
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johnwp06 Sat, 13 Mar 2010 15:48:27 GMT |
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| Coral |
•Origin – skeletons of marine corals; tropical seas
•Composition – aragonite
•Hardness: 3-4
•Colors – various
•Streak – white
•Luster – vitreous (when polished)
•Fluorescence – weak, violet. |
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johnwp06 Fri, 12 Mar 2010 02:10:16 GMT |
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| Shell |
•Origin – Aqueous mollusks
•Composition – calcium carbonate – CaCO3
•Hardness: 2.5-3.5
•Colors – various
•Streak – white
•Luster – dull, vitreous, pearly |
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johnwp06 Fri, 12 Mar 2010 02:10:16 GMT |
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| 2 Types of Amber |
1) Amber - Fossil Resin - millions of years old
2) Copal - Subfossil resin - thousands of years old |
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johnwp06 Fri, 12 Mar 2010 02:10:16 GMT |
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| Terpenes |
-organic chemicals in resins that give conifer trees aroma (which become linked as resin hardens) |
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johnwp06 Fri, 12 Mar 2010 02:10:16 GMT |
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| Amber |
-• From Latin, ambrum, after Arabic, anbar, meaning amber.
•Hardened tree resin (in sedimentary deposits)
-Wound is seals off by resin
-Before hardening a resin may trap bubbles, insects, etc.
•Composition: mix of organic resins
•Hardness: 2-2.5
•Colors: mostly yellow, brown, sometimes greenish
•Streak: white
•RI: 1.54 – amorphous compound
•Luster: Vitreous to resinous (polished)
•Fluorescence: bluish-white to yellow-green. Inclusions are common |
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johnwp06 Fri, 12 Mar 2010 02:06:16 GMT |
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| ”essence d’orient” |
-pearl simulate - made from fish scales for shininess |
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johnwp06 Fri, 12 Mar 2010 02:06:16 GMT |
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| Cultured Pearls |
•Pearls produced by oysters through the intervention of humans |
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johnwp06 Fri, 12 Mar 2010 02:06:16 GMT |
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| Baroque Pearls |
-pearls having unusual shapes |
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johnwp06 Fri, 12 Mar 2010 02:06:16 GMT |
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| Nacre |
-"mother of pearl", an organic-inorganic material produced by some mollusks as an inner shell layer; it is also what makes up pearls. |
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johnwp06 Fri, 12 Mar 2010 02:02:37 GMT |
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| Pearls |
-Origin of name – probably from Latin, perula, pearl
-Composition: calcium carbonate (CaCO3) + conchiolin (organic binding agent) + water
-Hardness: 2.5-4.5 (usually 3.5)
-Colors: Various
-Luster: pearly, iridescent (“orient”).
-Other: fracture uneven.
-Fluorescence: often pale green or reddish |
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johnwp06 Fri, 12 Mar 2010 02:02:37 GMT |
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Gold Plate (GP)
- Vermeil - |
-very thin layer of gold electroplated to surface of a base metal, often sterling silver |
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johnwp06 Fri, 12 Mar 2010 02:02:37 GMT |
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| Precious Metal |
-a rare, naturally occurring metallic chemical element of high economic value |
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johnwp06 Fri, 12 Mar 2010 02:02:37 GMT |
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| Platinum |
•A native element; symbol is Pt
•Name: derived from Spanish, platina, silver-like
•Color: whitish steel gray to dark gray
•Hardness: 4-4.5
•SG: 21.46 (pure); 14-19 alloyed
•Other characteristics: native platinum contains up to 28% iron, and is distinctly magnetic |
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johnwp06 Fri, 12 Mar 2010 01:56:17 GMT |
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| Tarnish |
a thin layer that forms from chemicals in the air over copper, brass, silver, aluminum, and other semi-reactive metals as their outermost layer undergoes a chemical reaction. |
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johnwp06 Fri, 12 Mar 2010 01:56:17 GMT |
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| Silver |
•a native element; symbol – Ag
-Symbol from Latin, argentums
•Color – silvery-white (usually)
•Hardness 2.5-3
-SG – 10.1-11.1, variable; develops a gray to black tarnish according to alloy |
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johnwp06 Fri, 12 Mar 2010 01:56:17 GMT |
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| Pyrite |
-"Fools Gold"
-Has similar appearance to gold; distinguished by being harder, and by brownish-black or greenish-black streak
-Brassy mineral disseminated in lapis lazuli |
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johnwp06 Fri, 12 Mar 2010 01:56:17 GMT |
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| Placer Deposits |
-alluvial deposits of precious metals; mainly flakes or nuggets |
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johnwp06 Fri, 12 Mar 2010 01:52:59 GMT |
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| Gold |
•a native element: symbol – Au
-symbol from Latin, aurum
•Color – Gold; usually
•Hardness – 2.5-3
•Streak – Gold-yellow (usually)
•SG – 19.3 (pure), decreasing w/ alloys
-Crystals in Cubic System |
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johnwp06 Fri, 12 Mar 2010 01:52:59 GMT |
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| Alloying |
-mixing of one or more metals. |
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johnwp06 Fri, 12 Mar 2010 01:52:59 GMT |
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| Diamond |
-Polymorph of Carbon
-Luster: Adamantine
-“diamante” or “adamas” – means “invincible”
-form at core-mantle boundary (high pressure, high temperature conditions); found in kimberlite
-10 on hardness scale
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johnwp06 Sat, 13 Mar 2010 16:12:08 GMT |
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| Zoisite |
-named after Baron von Zois
-strongly pleochroic
-crystals contain oil (hydro-carbon rich fluids)
-heat treated to remove tint and deepen blue color |
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johnwp06 Fri, 12 Mar 2010 01:46:42 GMT |
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| Garnet |
-"granatus" - Latin, grain in allusion to its appearance in the matrix, like seeds in a pomegranite
* "Singly Refractive"
-Luster: vitreous (adamantine in demantoid) |
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johnwp06 Sat, 13 Mar 2010 16:10:39 GMT |
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| Tourmaline |
-"turmali" - stone w/ mixed colors |
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johnwp06 Fri, 12 Mar 2010 01:46:42 GMT |
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| Feldspar |
-"feld" - field
-"splaten" - to split |
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johnwp06 Fri, 12 Mar 2010 01:46:42 GMT |
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| Jade |
-"Green"; ornamental stone valued for centuries in the Orient
-"thought to bring good luck" |
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johnwp06 Sat, 13 Mar 2010 16:34:37 GMT |
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| 2 Types of Jade |
Jadeite - pyroxene (single-chain jade)
Nephrite - amphibole (double-chain jade) |
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johnwp06 Fri, 12 Mar 2010 01:33:09 GMT |
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| Amphibole |
-Type of rock-forming mineral
-Double Chain |
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johnwp06 Fri, 12 Mar 2010 01:33:09 GMT |
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| Pyroxene |
-Type of rock-forming mineral
-Single Chain
-Jade |
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johnwp06 Sat, 13 Mar 2010 15:53:55 GMT |
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| Metamict |
-Crystalline minerals that lose their crystal structure due to radioactive destruction |
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johnwp06 Fri, 12 Mar 2010 01:25:15 GMT |
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| Curie |
-the amount of radioactivity in 1g of radium |
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johnwp06 Fri, 12 Mar 2010 01:25:15 GMT |
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| Isotropic Age Dating |
-way to determine gems age
-done through color and amount of damage they've undergone from radioactive decay |
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johnwp06 Fri, 12 Mar 2010 01:25:15 GMT |
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| Zircon |
-Type of gem
-Streak: White
-Crystals: Tetragonal -Luster: resinous to adamantine
-Doubly Refractive - causing obvious doubling of facets
-Contains Uranium & Thorium - which undergo radioactive decay |
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johnwp06 Sat, 13 Mar 2010 16:41:08 GMT |
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| Assembled Stone |
– 2 diff. stones put together
–also known as a - doublet |
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johnwp06 Wed, 10 Mar 2010 21:10:17 GMT |
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| Olivine |
-named for greenish color; due to iron
-periodot
hardness - 6.5 colors, yellow, olive green |
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johnwp06 Sat, 13 Mar 2010 16:11:03 GMT |
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| Obsidian |
-origin name, obsius, Roman
-hardness 5.5 -colors - black, brown, green, gray
-arrowheads |
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johnwp06 Wed, 10 Mar 2010 21:10:17 GMT |
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| 3 Types of Opal |
-Precious Opal - distinctive play of colors
-Fine Opal - yellow-red/orange color, no play of colors
-Common Opal - opaque, rarely translucent, no play of colors |
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johnwp06 Wed, 10 Mar 2010 21:10:17 GMT |
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| Opal |
-type of gem
-sanskirt, "opala"
-amorphous silicate mineral
-play of colors |
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johnwp06 Wed, 10 Mar 2010 21:05:50 GMT |
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| Tiger's Eye Quartz |
-type of chatoyancy in quartz
-gold-yellow, gold-brown |
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johnwp06 Wed, 10 Mar 2010 21:05:50 GMT |
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| Flint |
-fine grained quartz
-often found in Ohio creek beds |
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johnwp06 Wed, 10 Mar 2010 21:05:50 GMT |
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| Chalcedony |
-type of quartz
-banded, all colors
*petrified wood, bloodstone, jasper, carnelian, onyx |
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johnwp06 Wed, 10 Mar 2010 21:05:50 GMT |
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| Quartz |
-mineral breaks by fracture
-hexagonal crystals
-RI-1.54-1.55
*amethyst
*citrine
*chalcedony -
*carnelian |
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johnwp06 Wed, 10 Mar 2010 21:00:48 GMT |
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| Spinel |
-often mistaken as Ruby
-*octahedron crystals– double pyramid crystal form |
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johnwp06 Wed, 10 Mar 2010 21:00:48 GMT |
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| Chrysoberyl |
-Crystals – orthorhombic
-Colors – yellow, yellow-green, brownish, red, light blue
RI – 1.75-1.76
*alexandrite – extreme pleochrosim – color change in diff. lights; named after Czar Alexander II
*cymophane – “cat’s eye”, cymos, waving…phanos, light. |
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johnwp06 Wed, 10 Mar 2010 21:00:48 GMT |
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| Topaz |
-gem named after the Island of Topazos in the Red Sea
-crystals – orthorhombic -Luster – vitreous -streak - white
-pleochroism – yellow or pink
-formed as fluorine bearing vapors are given off in the last stages of solidification of igneous rocks
-occurs in cavities in rhyolite and granite (especially pegmatites) |
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johnwp06 Fri, 12 Mar 2010 01:21:35 GMT |
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| Topaz |
- named after the Island of Topazos in the Red Sea
crystals –orthorhombic -Luster – vitreous
-pleochroism – yellow or pink |
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johnwp06 Wed, 10 Mar 2010 20:49:34 GMT |
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| Emerald Cut (Step Cut) |
- type of gem cut
-developed because emeralds are brittle and prone to cracking when bumped. |
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johnwp06 Wed, 10 Mar 2010 20:49:34 GMT |
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| Beryl |
-"green stones" -Hexagonal Crystals
-Ring Silicates
-Aquamarine
-Emerald
-Heliodor
-Morganite
-Goshenite |
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johnwp06 Wed, 10 Mar 2010 20:49:34 GMT |
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| Asterism- Star Sapphires |
-star effect
-axes of star represent - Faith, Hope, Destiny
-travelers wore these to ward off harm |
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johnwp06 Wed, 10 Mar 2010 20:49:34 GMT |
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| Famous Corundum |
*Star of Bombay – blue sapphire, owned by movie star Mary Pickford
*Delong Star Ruby – red ruby, stolen for ransom in 1964 for $25,000
*Star of India – light blue star sapphire, donated to Smithsonian by JP Morgan
*Star of Asia –
*Carmen Lucia Ruby – 23 carat ruby set in a platinum ring owned by Peter Buck |
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johnwp06 Wed, 10 Mar 2010 20:44:19 GMT |
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| Diffusion Treatment |
-type of stone treatment
-color causing impurity added to the surface of a gem. Then heat. |
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johnwp06 Wed, 10 Mar 2010 20:44:19 GMT |
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| Heat Treatment |
-type of stone treatment
-causes changes in oxidation states of impurities; diffuses/spreads out impurities and color. |
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johnwp06 Wed, 10 Mar 2010 20:44:19 GMT |
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| Boule |
-synthetic crystal formed by flame fusion |
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johnwp06 Mon, 15 Mar 2010 00:21:04 GMT |
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| Verneuil Process |
*also knwon as flame fusion
*a way of producing synthetic corundum (rubies and sapphires |
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johnwp06 Wed, 10 Mar 2010 20:42:32 GMT |
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| Inclusion |
- mineral, gas or fluid w/in a crystal |
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johnwp06 Wed, 10 Mar 2010 20:42:32 GMT |
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| Corundum |
Ruby – from Latin, ruber, red.
Sapphire – from Latin, sapphirus, blue.
Composition: aluminum oxide, Al2O3 Luster: Vitreous
Harness: 9
Colors: colorless, red, blue... Streak: white
SG: 4
RI: 1.76-1.77
Crystals: hexagonal |
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johnwp06 Wed, 10 Mar 2010 20:42:32 GMT |
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