|
|
|
|
Decorative
Stones
Rhodonite
Rhodonite is manganese silicate. Crystals are not rare,
but found in only ., localities. Transparent material
from such crystals is occasionally -,red for collectors.
But of far greater significance to the gem trade is
massive Rhodonite. This is available in large quantities,
in colors ranging from rose-red and pink to brownish-pink.
Often the pink material is heavily mottled with dense
black patterns of manganese oxide, producing a very
attractive decorative stone.
Rhodonite occurs in Australia, Sweden, and the U.S.S.R.
in com¬mercial quantities.
|
|
Translucent
material is commonly made into cabochons and beads,
while more opaque Rhodonite is used for inlay -I. and
carving. Fine translucent beads can be costly, but cabochons
routinely sell for a few dollars.
Gem carvers use Rhodonite extensively because of its
toughness and interesting patterns. Hinged boxes, made
primarily in Germany, may feature thin Rhodonite slabs
overlaying white marble. |
| |
|
Spinel
Set prominently in the front of the Imperial State Crown of
England is a ;e red gem that flashes a fiery brilliance. This
stone is known throughout the world as the Black Prince's
Ruby. First recorded historically in 1367, the gem has followed
a long and romantic series of adventures, ultimately ending
its travels in the British Crown Jewels.
|
|
 |
 |
|
DIAMONDS,
GEMSTONES & CRYSTALS
FACTS & FIGURES |
| The
stones is enormous-2 inches across-and is simply
a polished, rough ass. Unfortunately, it is not
a ruby, as was so long thought. Rather, it is
,e of the world's finest examples of red spinel,
sometimes called “ballas ruby."
Spinel
is a fascinating gem that occurs in a wide range
of colors, including carmine-red, blood-red (so-called
"ruby spinel"), brownish-red, rose-red,
orange, pale blue, violet-blue, dark blue, purple,
greenish, and black. Star spinels are known but
are extremely rare. Spinel is a magnesium aluminum
oxide, but chemical substitution produces a variety
of other mineral species that share the same general
atomic structure. Pure spinel is actually colorless;
the wide variety existing colors is due to the
presence of impurities.
. 
Large
fine spinels are great treasures, yet few people
know of their existence. This is largely because
spinel occurs associated with ruby and sapphire.
For centuries therefore, spinel has existed in
the shad(). of its more prominent and valuable
cousins. |
|
|
 |
The
colors of gem spin( are intense and vibrant. The hardness
of II on the Mohs scale make spinel one of the harder and
more durable gems. Yet the price is kept low by lack of demand.
Ruby spinel is the most highly prized, yet will seldom reach
several hundred dollars per carat in price. A ruby of identical
appearance would sell for thousands of dollars per carat. |
 |
 |
 |
| diamond
1 | 2
| 3 | 4
|
|
|
|
