GEMSTONES

DEFINITION MINERALS that are cut RARE= valuable Usually above 7 on hardness scale

Gold Pure gold is malleable, heavy and expensive! Gold in jewelry is an alloy (mix of metals) K= % of gold 24K= 100% gold 14K = ?

The 5 C’s Cut Clarity Color Carat Cost

CUT Ground down on a grinding wheel Faceting- for TLT-TPT Lets light through mineral; adds brilliance Cabachoning- for OPQ

Diamonds in the “rough”

Round brilliant

Faceting

Cabachoning

Cabachons

Clarity Amount of imperfections Specs Cracks discoloration

Color Colored gems= deep color, more $$ Diamonds= D-Z scale (see handout) Exception is Z+ fancy diamonds are colored diamonds- most rare of all

D, Fl I 3

Fancy Diamonds More rare than traditional diamonds.

Carat Weight of gemstone 1 ct= 200 mg 100 pts.= 1 carat TGW= total gem weight for many stones together

Cost Depends on previous 4 C’s (especially clarity and color)

FAMOUS DIAMONDS

How Do Diamonds Form? Contrary to what many people believe, most diamonds do not form from coal

CULLINIAN 9

CULLINAN I STAR OF AFRICA 530 CTS.

Cullinan II: 317 cts.

Kohinoor Originally 186 cts. Now 108 cts. Queen of England

HOPE DIAMOND; 65 cts. New setting Nov. 2010

Smithsonian

Tiffany yellow

PINK- $2-3 million.

DeYoung Red 5.03 cts.

$5 million

Taylor-Burton Diamond (33 cts. -ring, $8 mill) 68 ct. necklace

Smithsonian diamonds

MILLENIUM STAR- 230 CTS D, IF (“Millenniums come and go, but a diamond is forever” DeBeers

The Regent Diamond 410 carat diamond when originally found. Later cut down to 140 carats. Today is at The Louvre.

Birthstones

Garnet January birthstone

ALEXANDRITE 1.6 ct $16,000

OPAL (hydrated quartz)

TOPAZ November birthstone

Emerald May birthstone

Peridot August Birthstone

Most expensive gemstones breaking-gemstones.php breaking-gemstones.php

Synthetic gemstones Advantages? Less expensive Less flawed Disadvantages?