|
|
|
|
Tourmaline
Tourmaline
occurs in pegmatite's, often associated with other gem
-minerals. Tourmaline frequently forms with quartz,
and crystal groups if tourmaline perched on large quartz
clusters are desired by collectors.
|
|
Localities
throughout the world are numerous, but gem material
is less widely distributed. Sri Lanka may well have
been the first source of this tem, and still produces
water worn pebbles of fine material in shades of yellow
and brown. |
| |
|
Most
of the world's tourmaline today comes from the state of Minas
Gerais, Brazil in a wide variety of colors. Some Brazilian
crystals can reach enormous size, several feet in length,
but such crystals are seldom of gem quality. Fine gem tourmaline
comes from the Malaga say Republic, South West Africa, Rhodesia,
and Mozambique. , the United States, Maine and California
are the most notable sources of tourmaline.
|
|
 |
 |
|
Tourmaline |
| Tourmaline
Recently
discovered deposits at Newry, Maine have yielded
fine crystals with a high percentage of gem material,
including some of the finest red and blue-green
stones in the world. Pala, California is a well-known
source of fine pink tourmaline..
The
dichroism of tourmaline is very strong, and crystals
are usually -it with the table parallel to the
length of the crystal.
Consumer
Tips-Tourmaline is available in the trade in large
quantities and in a huge array of colors, yet
it seems less well known than other gems. Tourmalines
are hard and durable and make tine ring stones,
especially when set with small diamonds. The price
ranges from a few dollars per carat to more than
$300 per carat, with large, flawless gems commanding
the premium prices. Brazil produces most of the
green and blue-green gems seen on the market,
but occasional stones from other sources may be
available at certain times and places.
Color
determines price among tourmalines; the most desirable
colors are a green resembling the color of fine
emerald, characteristic of chrome-tourmaline,
and lively pale-green shades, as well as the rich
reddish-pink of fine rubellite. Flawed stones
of any color are less desirable and less expensive
than "clean" stones, except in the case
of California rubellite and bicolored and tricolored
gems. These latter are most never completely free
of inclusions or minor internal flaws.
|
|
|
 |
Synthetic
gems created to resemble tourmaline cannot be distin¬guished
easily with the naked eye. Such synthetics are commonly
found in jewelry today, since tourmaline is the alternate
birthstone for October. The authenticity of a tourmaline
should therefore always be checked before purchase.
|
 |
 |
 |
|
Page 1 - 2 |
|
|
