November 18: Topaz

This month we thought we would follow the birthstone trail and take a closer look at some of the colors within the topaz family for the month of November.

Topaz suite: Pink cushion 4.97 cts. (Inventory #17535), imperial cushion 22.49 cts. (Inventory #17513), rose tapered emerald cut 4.76 cts. (Inventory #17532), golden cushion 53.80 cts. (Inventory #1643), yellow emerald cut 4.11 cts. (Inventory #5070), light blue emerald cut 9.76 cts. (Inventory #8679), blue pear shape 10.74 cts. (not inventoried). (Photo: Mia Dixon)

From the irradiated blues to the precious pinks, topaz can be an economical source of color for a neophyte, or a prize for the advanced collector. All the controversy of irradiated blues has surely softened that market, but many people are still enticed by the neon blue hues. Imperial topaz from the golden to red hues still are exclusive to a few mines in the Minas Gerais region of Brazil. As the supply seems fairly low but steady, and the demand keeps rising, it’s harder to match stones with collectors, causing prices to continue their ascent.

And if we refer to Kensho Okamoto’s table, listed below, we find that the topaz family helps to calm down, and cheer up, the mind. We all could use a taste of that medicine.

Interested? Select the inventory numbers above, call, or email us to inquire. [back to top]

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October 19: Phenomenal Gems

This month we feature two truly phenomenal gems.

As our curiosity for the natural wonders of the gem world matures we seem to appreciate truly fine phenomenal more and more. When the unique properties line up to create a show of light and color, we are mystified and enthralled by their beauty. As scientists we wonder how the conditions culminated and what elements coalesced to produce such a colorful and symmetrical gem: the right and left brain blending to an immaculate perception of these interactive jewels.

 

Burmese star ruby

This jewel combines the best properties one can expect from a star ruby. This stone, which features a truly pigeon’s-blood-red body color and a sharp, well-defined star, is from the Mogok Valley of Burma. It appears as a deep red gem under normal lighting conditions, but when hit by a ray of sun it comes alive.

Burmese star ruby. Inventory #16647, 5.18-carat oval cut, 9.82 x 7.92 x 5.87 mm. (Photo: Wimon Manorotkul)

Cat’s eye chrysoberyl

The second featured stone not only has a distinct eye but the body color glows a warm, golden lime hue. This jewel also exhibits the milk-and-honey effect, and can wink as well. We believe this chrysoberyl comes from the Arusha region in northeastern Tanzania because of its unique electric lime body color and its velvety appearance, but it may be of Sri Lankan origin.

Cat’s eye chrysoberyl. Above, a single light source illuminates the sharp, centered eye with a hint of the milk-and-honey effect. Below, the eye will open and close as two light sources are used, keeping one stationary while rolling the other perpendicular to the eye. A fun trick for any gem lover. Round, 13.25 carats, 12.75 x 7.89 mm. Price upon request. (Photos: Jason Stephenson)

Interested? Call or email us to inquire. [back to top]

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September 15: Red Zircon from Tanzania

This month we had a power struggle amongst contenders for Pala’s featured gemstone. The victor was a late entry, but it easily eclipsed the competiion. We are pleased to present for September a substantial (not the least due to its weight of 152.47 carats), purportedly-natural red zircon from Tanzania.

Bill Larson gives us the background:

This is the largest fine red zircon I have ever seen. It is said to be from newly mined material in Tanzania and unenhanced. But note: Pala has not certified this gem with GIA yet. It was shown directly from a master Thai cutter through a friendly, serious gem dealer in Bangkok before he had even purchased the gem. We did an immediate negotiation, and Pala owns said gemstone.

Super-sized. Orangy-red zircon from Tanzania, 152.47 carats, 26.1 x 25.9 x 20.1 mm. (Photo: MIa Dixon)

In the sun this zircon glows like a red coal. A slight orange secondary color makes it superbly beautiful. In artificial light it glows red. This is a museum-quality gem.

Interested? Call or email us to inquire. [back to top]

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August 19: Chrysocolla Suite

This month we feature a stunning suite of chrysocolla from the Globe Hills of Arizona. This neon-blue gem silica is reminiscent of a paraiba color due in part once again to the presence of copper. These stones feature a beautiful, even Caribbean-blue color with a few subtle clear veins running through the material. Cabochons were cut from same piece of rough so the 11-piece set has uniform color and sets up nicely for a necklace layout.

Gem chrysocolla suite, 11 pieces with a total weight of 34.68 carats, ranging in size from 11 x 8 to 15 x 21 mm. Inventory #17488. (Photo: Jason Stephenson)

The suite was carved by San Diego artist Bud Standley, who now has a studio in Balboa Park’s Spanish Village Art Center.

Below is a piece of rough chrysocolla, also from the Globe district in Arizona, displaying the electric blue hue and a layer of druse covering some of the botryoidal formations.

Rough chrysocolla specimen, 4.6 x 3.6 x 2.1 cm. Inventory #17401. (Photo: John McLean)

Interested? Select the inventory numbers above, call, or email us to inquire. [back to top]

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July 16: New Dawn of Demantoids

This month we feature an exquisite new demantoid garnet from Russia. This 3.51-carat jewel has a succulent green hue, medium tone, and full saturation. Inside, we find a fine example of the diagnostic horsetail inclusion.

Russian demantoid garnet, above, 3.51 carats, dimensions 9.38 x 5.8 mm. Below, the same demantoid under different lighting conditions, bringing out the phenomenal dispersion from within. (Photos: Above, Mia Dixon; Below, Jason Stephenson)

Recent mining ventures in Russia have begun to produce new demantoid garnet material. Pala is once again involved with distribution and we have a fine selection to offer. Extremely saturated greens in all shapes and sizes, many with superb examples of horsetails and some other intriguing inclusions.

Aurora adamantis. The aurora-like inclusions above are actually interwoven bands of horsetails. This is from a 2.33-carat round, 7.3 x 5.0 mm. (not from our featured gemstone).(Photomicrograph: Jason Stephenson)

Some of these quiescent internal formations seem to resemble other active formations on a grander scale. The radiating horsetail spray with a definable core resembles an exploding firework. The interwoven bands of horsetails are reminiscent of the liquidity and beauty of the aurora borealis.

Pow! An inclusion mimics a firework spray. From a 1.21-carat round, 6.0 x 4.0 mm. (Photomicrograph: Jason Stephenson)

These micro to macro associations gives us a little insight into the complex dynamics that are at work during crystallization of these demantoid garnets. Heat, pressure, and chemistry meet in a unique situation in time and space. Beauty is found on many scales.

Suite of Russian demantoid garnet, (clockwise from left) 1.97 carats, 7.46 x 6.25 mm.; 3.51 carats, 9.38 x 9.38 mm.; 1.15 carats, 6.07 x 5.44 mm.; 1.28 carats, 6.68 x 6.68 mm.; 1.98 carats, 7.41 x 7.41 mm.; 1.73 carats, 7.23 x 7.23 mm. (Photo: Mia Dixon)

Interested? Select call or email us to inquire.
 

 

For other information on demantoid garnet:

• Reds Turn to Green: Russia’s Stunning Demantoid Discovery
• Demanotoid – From the Ural Mountains of Russia
• Update on the Karkodino and Babrovka Mines (May 2000)
• Search for demantoid garnet on Palagems.com

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June 23: Sunstone from Tanzania

This month we feature a mesmerizing sunstone from Tanzania. This unique variety of feldspar requires a closer look as flashes of spectral colors come firing out of the stone. Geometric platelets fill the inside of this jewel like confetti at a tickertape parade or looking into an active psychedelic snow globe.

Sunstone from Tanzania, Arusha Region, 20.37 carats, 29 x 15.3 x 8.9 mm. Inventory #17383. (Photo: Mia Dixon)

These randomly oriented inclusions are hematite platelets, a product of exsolution, and exhibit a rainbow of interference colors as the light passes through at different angles. The hematite platelets display mainly a reddish orange hue, which gives this stone its warm body color. This beautiful gemstone would work well in a designer pendant or simply as a collector’s stone demonstrating these unusual internal characteristics.

Party colors. Photomicrograph showing the illuminated hematite platelets. (Photo: Jason Stephenson)

Interested? Select Inventory #17383, call, or email us to inquire.

See also this February 2005 article, “On the Horizon: In search of East Africa’s eye-catching Maasai sunstone,” from Lapidary Journal Jewelry Artist. [back to top]

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May 21: World-Class Lavender Hackmanite

A phenomenal variety of sodalite and a member of the feldspathoid group, hackmanite is mostly found in a translucent cabochon form. This month we feature a transparent faceted hackmanite from Afghanistan. This gem is near-flawless and exhibits all the unusual optical characteristics associated with hackmanite.

Lavender hackmanite from Afghanistan, 7.87 carats, 16.28 x 11.08 x 8.64 mm. Inventory #17382. (Photo: Mia Dixon)

Hackmanite is known for its unique color-shift phenomenon when subjected to warm white light or daylight. The phenomenon is known as tenebrescence. Hackmanite will often increase in saturation when allowed to be “charged up” in daylight and sometimes shifts between lavender and magenta hues. Long-wave ultraviolet light also brings out an amazing fluorescence, as seen directly below; in this case we see a glowing orange/yellow hue. The distinctive color phenomena are derived from the sulphur component in hackmanite’s chemistry. Light can polymerize the sulphur into different-length molecules and ions that, in turn, have different colors. (Thanks to Dr. George R. Rossman for clarification of the color phenomena science. See this Caltech webpage for more on the sodalite group.)

Long-wave ultraviolet light shows off the fluorescence of this hackmanite. (Photo: Mia Dixon)

An amazing feature that is illuminated by the unusual optics of this stone is seen when a beam of long-wave UV light is shot through the table. You can actually see the refraction of light as it travels though the stone: entering the table, bouncing off the pavilion, and traveling back out the table. A living example of all the diagrams you’ve seen drawn with stick figures in gem books. Like a laser through smoke the path of light is captured by the internal structure of the gem, and highlighted by the facets and form of this hackmanite.

A beam of long-wave ultraviolet light demonstrates the refraction path. (Photo: Mia Dixon)

Interested? Select Inventory #17382, call, or email us to inquire. [back to top]

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April 16: Aqua-marine

This month we feature a dazzling aquamarine. In the gem trade aquamarine most often refers to the blue variety of beryl, but the first element of this compound word actually implies some green. Even Webster’s Dictionary defines aqua as “a light greenish blue color.” Today most pure-blue aquamarines are heated from greenish blue rough; the heated process removes the secondary green hue and leaves only the blue hue.

A flawless 22-carat natural aquamarine with an exquisite radiant-style faceting. Inventory #15579. (Photo: MIa Dixon)

Our featured aquamarine exhibits the beautiful blend of blue and green in its natural state. It’s reminiscent of open ocean water, which is of course implied by the second element of the word: marine. Major producers of gem-quality aquamarine today are Brazil, China, and several countries in Africa.

Interested? Select Inventory #15579, call, or email us to inquire. [back to top]

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March 18: Bi-Color Topaz

A new look at an exceptional gemstone

This month’s featured stone comes to us from Brazil and is precious and imperial in many ways.

When we’re talking about topaz, imperial is a descriptive term for golden orangey-yellow hues, and precious is usually reserved for the more pink-red hues. However, these terms can, and often are, used interchangeably by gem dealers. Exceptional colors like these are only found near the town of Ouro Preto within in the state of Minas Gerais in Brazil.

Bi-color topaz, 13.35 carats, 27 x 11.8 x 5.42 mm. Inventory #15507. (Photos: Jason Stephenson)

The top half of the stone exhibits the classic golden color, while the bottom seems to collect all the rich rosy pink color. This combination of color is extremely rare to find within the same stone—not to mention a flawless interior. And the origin of color in this jewel is natural; the original crystal actually exhibited these two distinct hues. (Oftentimes rich imperial colors can be heated to produce the pinkish hues.) A true collector’s gem fashioned to fit nicely into a one-of-a-kind pendant.

Stoked. Oblique angle of the topaz showing the fire within. Savvy readers may recall this stone accompanying a Gem News story last October; we thought it deserved a second look… (Photo: Jason Stephenson)

Interested? Select Inventory #15507, call, or email us to inquire. [back to top]

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February 25: From the Rough

An assortment of newly acquired gems that were bought
in the rough at this year’s Tucson show

One fun and curious aspect of the Tucson show is the chance to roll the dice and buy rough crystals of various colored stones in hopes that they will morph into beautiful gems. Evaluating the rough and trying to imagine what the finished stone will look like can be enjoyable. There’s always a gamble when buying rough gem material, but the payout can be surprising and rewarding.

Smooth around the edges. All five of this month’s featured gemstones came from unfaceted material obtained by Pala International at this month’s Tucson show. (Photo: Jason Stephenson)

This month we feature a few jewels that came from the rough and into the light as happy, newborn jewels. A 36.67-carat large oval greenish-yellow apatite from Mexico, a 7.57-carat elongated cushion umbalite garnet from Tanzania, a 1.91-carat small cushion pinkish red spinel from Tanzania, a 2.80-carat trilliant chrome tourmaline from Tanzania, and a 6.42-carat cushion rubellite tourmaline from Nigeria.

Interested? Call or email us to inquire. [back to top]

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January 19: Rhodochrosite from a New Locality

Pala International obtained a parcel of rough rhodochrosite at November’s West Coast Gem & Mineral Show in Costa Mesa, from a locality that has yet to be confirmed. We will keep you posted as the mystery of origin unfolds.

Selection of the new rhodochrosite material; sizes ranging from 2.5 to 10.5 carats. (Photo: Mia Dixon)

The material is the classic, beautiful pinkish-red hue, with more peach or orange secondary than some of the other rhodochrosite localities. Reminiscent of a padparadscha sapphire, with a pleasing blend of colors and a fluorescent glow. There are several localities around the world that produce rhodochrosite mineral specimens but there are really only two that produce facetable rough in quantity and quality: the Kalahari manganese fields of South Africa, and the Alma District of Park County in Colorado.

Here is a fine example of what Colorado can produce: a 19.78-carat round brilliant, 16.8 mm in diameter. This stone has been sold. (Photo: Jason Stephenson)

Displaying these three examples, you can see the unique variations of red produced by each deposit. Production from South Africa and Colorado is extremely limited; however, the new material is available now.

Another example of a fine rhodochrosite, this time from South Africa: 16.27-carat oval brilliant, 20.21 x 13.41 mm. From the Gladnick collection. (Photo: Jason Stephenson)

Interested? Call or email us to inquire. [back to top]

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See 2005–2008 Featured Stones here.