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| Watermelon tourmaline, courtesy Pala International. |
Tourmaline, first introduced to Europeans in 1703 as an
import from Ceylon, gets its name from the island nation’s word touramali,
which means “stone with mixed colors.” It is an apt description for a colored
gemstone that comes in more than 100 colors, more hues, shades and nuances than
any other gemstone. Some tourmaline varieties even exhibit two or three colors
within the same stone. One of the most desirable varieties of the tourmaline
family is the “watermelon” tourmaline, so-called because its green outer rim
around a pink or red center resembles that fruit. The term was coined by George
Robeley Howe, who lived from 1860 to 1950 in Maine, a source of many varieties
of tourmaline.
The watermelon tourmaline’s crystals also can display three
distinct colors: green, as in the outer skin of the watermelon, pink or red for
the sweet fleshy core of the fruit, with white between the two colors,
representing the rind. Reinforcing the fruity connection, the stone is often
cut in thin slices similar to the way watermelon is cut.
The appeal of the stone stems from its rich saturation of
color. “It’s the two colors together: The crystals are glassy and lustrous with
those pretty colors, and sometimes you can see into them or see through them,”
says dealer Dan Weinrich of Weinrich Minerals, Inc. in Grover, Missouri.
While lighter or darker coloration is a matter of personal
preference, in general, the most desirable stones have a more visible color
separation. “You have two colors, the pink and the green, so you want to look
at how saturated it is on both sides,” says importer and retailer Adam Gil,
president of Paraiba International in New York City. “There is a separation
between the two colors, so you want to see how defined the separation is and
how well the colors contrast.”
“Tourmaline is one of the most complex mineral groups,” says
Jason Stephenson, a graduate gemologist and geologist with Pala International
in Fallbrook, California. Different elements in the earth cause its varied
color combinations. In watermelon gems, for example, iron causes its greenish
coloration, while lithium and magnesium trigger the pinks and reds.
“As the crystal is growing, it will eat up certain elements
to produce sections of the stone,” Stephenson explains, noting that the
majority of watermelon tourmaline is natural. “They pretty much come out of the
ground like that,” he says. Some dealers suspect a small percentage may be heat
treated with a low-temperature process to permanently enhance the natural color
of the stone and increase its price, but treatments do not alter the chemical
makeup of the stone. Such treatments are difficult to detect without the use of
high-powered lab equipment, which makes the cost of detection somewhat
prohibitive.
Afghanistan, Nigeria, Southern California, Madagascar and
Brazil are all current sources of watermelon tourmaline. Though there is still
a supply from these areas, it is dwindling and “across the board, there’s not a
lot of new material coming out of the ground. We’d love to have more watermelon
tourmaline, but it’s not there,” Stephenson says.
The most notable finds in the past ten years have been in
Afghanistan and it is the largest current source of the gem. “There’s more
consistent mining of all tourmalines in Afghanistan, including watermelons,”
Stephenson says, who notes that scattered, occasional finds range from “the
size of a basketball to the size of a small car.” Experts say while there is
not always an easily discernable difference in material, Nigeria and Madagascar
tend to produce darker, deeper colors, while the San Diego, California,
material is, in general, lighter, though “it’s hard to tell what the origin is
sometimes, because the composition can be identical in different countries,”
Gil explains.
Watermelon tourmaline has a royal past. Empress Dowager Tz’u
His, the last empress of China, who ruled during the latter half of the
nineteenth century, loved pink and red tourmaline. When high-quality pink gems
were discovered in San Diego, she acquired as much as she could. “As the number
of wealthy grew in China, they knew of tourmaline because the empress
popularized it,” Stephenson says. Today, the rosy quality of watermelon
tourmaline is still sought after in China and “the Chinese are buying it up in
larger sizes,” he adds.
This demand from China has contributed to significant recent
price increases for watermelon tourmaline, with experts noting the price has
doubled in the past ten years. “It’s got to be something a little different,
with sharper color. Anything truly
unique and desirable is always going to go up in price,” Weinrich notes. Today,
fine-quality watermelon stones typically range from about $300 to $600 per
carat, but can go up to nearly $1,000 for a truly world-class stone. The better
slices show the full range of color, from green to white to pink, Ward says. “Smaller
ones that show all the colors are highly valued,” he notes.
Watermelon tourmaline is an ideal choice for a jewelry
wearer “who wants to be a little funky and different — someone who’s a little
more savvy would generally ask for it,” Gil notes. Designer and retailer Jamie
Ward, owner of Juno in San Francisco, says he’s been using watermelon
tourmaline in many of his recent creations, ranging from earrings to ankle
bracelets, because of its rich color range. “I use lots of small, round stones,
pear cuts and chandelier cuts. Sometimes, the cut of the stone will give you
the design,” Ward says.
Small, round stones showcase the range of color
possibilities in watermelon tourmaline, whether it’s pea green or grapefruit in
color. But, “it takes a larger piece of at least half a carat to show more than
one color and the full color range,” Ward says. He adds, “I like catching a
piece that has the whole slice.” Gil notes that watermelon tourmaline is an
especially lovely choice for rings in the fine jewelry market, mostly in the
5-carat to 7-carat range. “For the most part, the material lends itself to an
emerald or cushion cut,” Gil notes. “Once it’s set, it’s durable. Just picture
it on your finger — it’s a beautiful stone and it’s different. Being unique is
always a good thing.”
After all, its happy hues and cheerfully uncommon tricolor
structure can make even the most savvy jewelry maven feel like a kid in a candy
store. Like a juicy slice of watermelon on a hot summer day, this colored gem is
a satisfying treat.
Article from the Rapaport Magazine - October 2012. To subscribe click here.