January Birthstone: Garnet

Wide Variety of Garnets

Most people do not realize garnets come in a wide variety of gem types and colors, with many cutting options.

Garnets are a set of closely related minerals that form a group, resulting in gemstones in almost every color. Red garnets have a long history, but modern gem buyers can pick from a rich palette of garnet colors: greens, oranges, pinkish oranges, deeply saturated purplish reds, and even some blues.

Red garnet is one of the most common and widespread of gems, found in metamorphic rocks (which are rocks altered by heat and pressure) on every continent. But not all garnets are as abundant as the red ones. A green garnet, tsavorite, also occurs in metamorphic rocks, but it’s rarer because it needs unusual rock chemistries and special conditions to form.

Demantoid is a rare and famous green garnet, spessartine (also called spessarite) is an orange garnet, and rhodolite is a beautiful purple-red garnet. Garnets can even exhibit the color-change phenomenon similar to the rare gemstone alexandrite.

All garnets have essentially the same crystal structure, but they vary in chemical composition. There are more than twenty garnet categories, called species, but only five are commercially important as gems. Those five are pyrope, almandine (also called almandite), spessartine, grossular (grossularite), and andradite. A sixth, uvarovite, is a green garnet that usually occurs as crystals too small to cut. It’s sometimes set as clusters in jewelry. Many garnets are chemical mixtures of two or more garnet species.

Understanding Group, Species, and Variety Chart

Garnets are a group of closely related mineral species with many different color varieties.
For more info on Garnet, please click on link:

Blue Zircon…also Dec. birthstone

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Zircon is an important jewelry gemstone which is sometimes confused with the cheap and ubiquitous synthetic stone known as cubic zirconia. Of course the two are totally distinct in their chemistry, optical properties and origins.  Zircon is a natural material (zirconium silicate) which is found in Cambodia, Burma and Sri Lanka as well as in Brazil, Australia and East Africa. Colorless when pure, zirconium silicate takes on various shades due to impurities. The brilliance and fire of this gemstone makes it very popular and it is attractively priced in comparison with many other fine gems. The wide variety of colors of zircon, its rarity, and its relatively low cost make it a popular collector’s stone. Collectors enjoy the search for all possible colors and variations. Zircon is also a favorite of gemologists and geologists for its unique properties
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The prices and values of fine zircon vary depending on the size and quality of the gemstone.  Blue is the most popular zircon color, followed by honey, red and white. Green zircon, resulting from the effects of natural radioactivity, is rare. In blue zircon, look for a saturated blue. Clean gems in large sizes are especially valuable.
Image result for tiffany blue zircon ring

October Birthstone: Opal

opal-ring

While the colorful glory of the opal is undeniably striking. Opals range in color from white to black, with glints of yellow, orange, green, red and blue. They derive their name from the Greek word Opallos, which means “to see a change (of color).” Opals were formed by non-crystalline silica gel that seeped into crevices within sedimentary strata. Over time the gel hardened to form opals. They’re essentially composed of particles closely packed together in delicate arrangements. When these particles are packed together in a regular pattern, they create a three-dimensional array of spaces – which create the opal’s unique radiance.

For more info: http://www.gia.edu/opal

 

September birthstone: Sapphire

Sapphire is a popular gemstone – and comes in a rainbow of colors. It’s also been long prized, from Ancient Greek rulers to the clergy of the Middle Ages. But where does the September birthstone come from?

A Little Bit about Sapphire

Sapphires in a range of colors

Before we embark on our journey to find the September birthstone, let’s start with a little gemological background.

The September birthstone, sapphire, comes in a range of colors: blue, violet, green, yellow, orange, pink, purple and intermediate hues. The gem belongs to the mineral species corundum: corundum is colorless, but trace elements or color centers (small defects in the atomic structure of a mineral that can absorb light and impart color to the stone) can turn colorless corundum into colorful sapphire. Red corundum is the only color not called sapphire; corundum with this color is ruby.

Where Sapphires Come From: Kashmir

3.08 ct unheated Kashmir sapphire

Blue Kashmir sapphire is legendary among gem collectors and jewelry connoisseurs. However, its reputation for gems of unsurpassed beauty rests on stones mined from 1881 to 1887; very little has been produced since then. Sapphire from the mines after this brief window in time varied greatly in quality.

Finding the September birthstone in Kashmir reads like a chapter from an adventure book: we go to northern India, past the picturesque Dal Lake and its famous houseboats, beyond fields of wildflowers and head up into the Himalayas. Our journey takes us on treacherous roads to, as 18th-century explorers described, a “region beyond the snows.” In these remote hillsides, some of the world’s most beautiful sapphires were unearthed.

Srinagar

Fine blue Kashmir sapphire is said to resemble the color of the feathers of a peacock’s neck. Tiny inclusions give gems a velvety appearance. This can look like an extremely fine haze.

A few last facts about Kashmir sapphire: perpetual snow cover makes mining extraordinarily difficult; the mines are exceedingly remote; the weather is severe; and the area is politically contested. Few stones sporadically emerge, and fewer gemologists have researched the mines. That means you’re highly unlikely to find Kashmir sapphire for sale, and if you do, you’ll want a GIA Colored Stone Identification & Origin Report to verify its country of origin. Fine pieces are occasionally sold by leading auction houses.

Blue sapphire

Where Sapphires Come From: Myanmar

rough sapphire crystal

The land north of Mogok, a city in Upper Myanmar. Blue sapphires mined in Mogok tend to have a rich, intense hue; the best of these September birthstones maintain their appearance under all lighting conditions: incandescent, daylight and fluorescent.

Miners outside of Sapphire mine in Mogok

The sapphire mines of Mogok share some similarities with the ones from Kashmir: they are remote, hard to reach and are in a politically-charged land. Sapphires from this locale are also rare; they are found near many of the ruby deposits. Mogok is also famed for producing some of the finest pink sapphires in the world.

oval shape 6.39 ct pink sapphire

Where Sapphires Come From: Sri Lanka

Sri Lanka can poetically be called “Treasure Island”. All colors of sapphire, ruby, cat’s-eye chrysoberyl, spinel, garnet, tourmaline, topaz, quartz and many other gems can be found in the Highland Complex, a wide band that runs roughly down the middle of the island. Some of the finest sapphire is also found here, and in riverbeds scattered across the country.

Miner searching in river gravel

33.16 ct blue sapphire

6.66 ct padparadscha sapphire

Sri Lanka is perhaps the most famous source for padparadscha sapphires; they are found in river gravel throughout the country. Padparadscha means “lotus flower,” in Sinhalese and this name has been given to the pinkish orange to orange-pink variety of corundum. This sapphire’s color has been likened to the color of salmon, sunset and ripe guava. The cause of color for padparadscha sapphire is due to either trace amounts of iron and chromium or color centers. Fine specimens can sell for as much as a ruby.

Sri Lanka is also a source of the September birthstone in many of its colors: green, yellow, pink, purple, and virtually any color in between. Many in the trade consider Sri Lanka to produce the best range of fancy color sapphires in the world.

Where Sapphires Come From: Thailand

Thailand is an important source of sapphire. Gem fields in Chantaburi, in southeastern Thailand, were mined from the late 1800s to the early 1900s. Sapphire now mostly comes from Kanchanaburi (western Thailand), where it is found in rivers and streams. Most sapphire mined in Thailand is heat-treated to improve its color.

Sapphire mines in Kanchanaburi

Thailand is one of the world’s major cutting and treatment centers: sapphire from Myanmar, Cambodia, Australia, Madagascar and Sri Lanka are sent here, and end up in jewelry stores in the United States, Japan and Europe.

Art Deco bracelet

Where Sapphires Come From: Cambodia

On the western side of Cambodia—in the Pailin Province, near the border with Thailand—sapphire rough lies in riverbeds. Miners sift through the gravel, looking for “Pailin sapphire,” which is understood to be fine-quality blue sapphire that is typically water-worn, rounded and hexagonal in shape. Stones are regularly heat-treated to lighten color and remove or reduce inclusions.

Pailin, Cambodia

Mining for sapphire in Pailin is extremely demanding. Deadly malaria and a hot climate are working conditions that require muscle and grit. The Khmer Rouge, an oppressive regime that ruled Cambodia from the 1970s to the 1990s, left a legacy of poverty and landmines that still take lives and limbs. Still, in the midst of these most difficult circumstances, miners search for a piece of rough that can change their fortunes.

Two 11.48 carats blue sapphires

Where Sapphires Come From: Madagascar

Three blue sapphires

Madagascar, an island off the southeastern coast of Africa, is a rich source of gems: garnet, aquamarine, tsavorite, rubies and of course, the September birthstone. Rough sapphire was found in 1993 in the Andranondambo region of southern Madagascar; and in 1998 in IIakaka – a remote, arid land of plains broken by lonely mountains. A new source was found in January 2016 near Andranondambo in an extremely remote and dangerous location. The mine is accessible only by foot, and the area is rife with bandits.

Sapphire mining in Madagascar

Many people rank the color of Madagascar’s blue sapphires between Kashmir and Sri Lanka in quality. Rough is often heat-treated to improve color. Slight inclusions are common, as well as color zoning (bands of color).

Two heat-treated Madagascar sapphires

Madagascar is another source for fancy color sapphire: it produces pinks, blue-violets, yellows, oranges and greens.

Range of different colored sapphires

Where Sapphires Come From: Other Sources

The September birthstone can also be found in other areas of the world. Australia produces blue, yellow and green sapphires. It is primarily a source of commercial-grade sapphire, and occasionally produces high-quality rough suitable for use in fine jewelry. Commercial-grade sapphire is also found in Montana. Tanzania, Malawi and Kenya – countries in East Africa – are other sources of pink, blue-violet, yellow, orange and green sapphires.

Heat treated yellow sapphire (left) and untreated yellow sapphire (right)

18K yellow and rose gold flower pin

 

Courtesy of GIA

 

August birthstone: Peridot

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While the 64.57-carat cut peridot is magnificent, it is overshadowed by the amazing 7.9-cm tall crystal. Both are from Sappat, Kohistan, Pakistan- Jeffrey Scovil.

Gem miners find peridot as irregular nodules (rounded rocks with peridot crystals inside) in some lava flows in the United States, China, and Vietnam and, very rarely, as large crystals lining veins or pockets in certain types of solidified molten rock. Sources for the latter include Finland, Pakistan, Myanmar, and the island of Zabargad.

Suite of Peridot Jewelry

This incredible suite of peridot jewelry has a total weight of 350.40 carats. All are top-quality peridots from Pakistan. – © GIA & Harold & Erica Van Pelt.

Geologists believe both types of deposits relate to the spreading of the sea floor that occurs when the earth’s crust splits, and rocks from its mantle are pushed up to the surface. Sometimes—as in Myanmar— these rocks can be altered, deformed, and incorporated into mountain ranges by later earth movements.

Rarely, peridot can have an extraterrestrial source, being contained in meteorites that have fallen to earth.

The color range for peridot is narrow, from a brown-green color to yellowish green to pure green. Yellowish green is the most common peridot color seen in jewelry.

Princess Cut Peridot

Peridot is best known for its yellowish green color.

Peridot is the gem variety of the mineral olivine. Its chemical composition includes iron and magnesium, and iron is the cause of its attractive yellowish green colors. The gem often occurs in volcanic rocks called basalts, which are rich in these two elements.

Healing Sisters

These peridots from Peridot Mesa in the San Carlos Apache Nation, Arizona, are set in a jewelry style called “Healing Sisters.” – Courtesy Apache Gems

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Courtesy of GIA