GARNET – Introduction

 Image credit: GIA

Many people born in January think the most common and widespread red garnet is their birthstone. This January birthstone, in fact, comes in the greatest variety of color!

Members of the garnet family belong to a set of closely related mineral species that form a group: same crystal structure yet different chemical composition.

There are 5 common species that are commercially important as gems: Almandine, Pyrope, Spessartite, Grossularite, and Andradite. The 6th, Uvarovite, is a rare green garnet often occurring as crystals too small to cut. It doesn’t have much commercial importance and is usually set in jewelry as clusters.

The deep red variety we normally associate with is the almandite garnet. Other worthy garnets include the green “demantoid” and “tsavorite,” the orangy red “hessonite” and the pink/red “rhodolite.”

Another variety of garnets exhibit optical phenomena because of mineral inclusion to display asterism (star-shaped pattern), chatoyancy (cat’s eye) or color change.

Today, the most important sources for garnet are Africa, Sri Lanka, and India.

January babies and gemstone enthusiasts, you are spoilt for choices!

GARNET – Ancient Jewelry

Evidence of garnet jewelry dated back to ancient civilization where garnet jewelry was found buried with mummified corpses as prized possessions for the afterlife.

Top left picture:

3,000 year old Pectoral of Kheper Scarab: A carved red garnet in the shape of scarab beetle forms the centerpiece of this Egyptian breastplate.

Top right picture:

Middle Kingdom Pectoral and Necklace of Princess Sithathoryunet: The cloisonne pectoral is inlaid with 372 carefully cut pieces of semiprecious stones including garnet.

Bottom picture:

Blown up picture of the pectoral

 

 

 

 

 

 

 

Garnets were also prized in ancient Rome jewelry from hair ornaments, earrings, necklaces, armbands, to rings. Seal rings, as in signet rings with carved garnets, were used to stamp wax that secured important documents.

1st row
Hair ornament (220 – 100 BCE)
Earring (2nd – 1st century BC)
Seal ring (300 – 100 BC)

2nd row
Necklace (3rd – 2nd century BC)
Armband with Hercules Knot (3rd – 2nd century BC)

3rd row
Intaglio ring (3rd – 2nd century BC)
Ring (3rd century BC)

 

 

 

 

 

 

 

Garnets were also very popular gemstones with the Germanic tribes used for cloisonné inlay work.

 

Top:

Gold and garnet-inlaid mounts from a sword harness found at Sutton Hoo burial (7th century CE)

 

Bottom:

Kingston brooch (7th century CE)

 

Red Garnet – Rhodolite

In traffic light order, red garnets will be discussed first.

A recap of the common species in the big garnet family: Almandine, Pyrope, Spessartite, Grossularite, Andradite, and the rare green Uvarovite.

Most red garnets are mixtures of pyrope and almandine. When you see dark-toned, reddish brown, calibrated stones in in inexpensive, mass market jewelry, they are likely to be pyrope-almandine garnets.

Rhodolite is the most valuable of the red garnets. Its color ranges from dark purplish red to light reddish purple hue. The best quality comes in medium to medium-dark tone.

 

Not many are aware that a fine rhodolite can look like a fine ruby. A rich purplish-red rhodolite can be a less-costly alternative to red tourmaline.

Given that rhodolite’s rough is plentiful, its availability makes it ideal for fantasy and designer cuts instead of facets. First discovered in North Carolina, USA, East Africa has been the most important source in recent years.

 

Red Garnet – Pyrope

During the Victorian era garnets were extremely fashionable; rose cut pyrope garnets from the Czech Republic often covered entire jewelry items.

Better known as Bohemian Garnets after the area they were mined – Bohemia, pyropes as large as hens’ eggs have been found. They are also known as cape ruby.

In the 1900s however, elaborate and gem-studded jewelry fell out of fashion. The demand for pyropes never recovered. Today, the area still supports a local cutting and jewelry manufacturing operation that sells products reminiscent of Victorian times.

Pyropes from other sources such as Arizona and Utah, USA, are marketed as “anthill” garnets. The best stones from these sources are a highly desirable intense pure red – easily mistaken for good quality ruby.

Red Garnet – Almandine

Most dark red gemstones in the market are either almandine or pyrope. While usually almandine is the darker and heavier of the two, they can be very difficult to distinguish.

In many old pieces of jewelry, almandine garnets were set with reflective foil backings to improve their dark appearance. Or they were cut with very shallow proportions.

Another ancient method is to cut a cabochon with a curved undercut bottom to lighten the tone. The finished stone is called a hollowback.

Orange Garnet – Spessartite Specimens

 

Once upon a time, this species of the garnet family was a rare garnet known only to collectors. Named after the Spessart district of Bavaria, Germany, where it was first discovered, this orange gem was only available from just a few exceptional sources

New discoveries in the 1990s especially Nigeria helped propelled the availability of spessartite in calibrated sizes of good color. It’s the most popular orange garnet today.

These are spessartite garnet specimens with:

Microcline quartz (left)
Smoky quartz (top right)
Orthoclase quartz (bottom right)

Image credit: minfind and exceptionalminerals

 

Multiple, isolated burgundy red spessartite garnet crystals with doubly-terminated smoky quartz prisms on awell-crystallized feldspar matrix.

This combination specimen is a world-class specimen.

Source: Shigar Valley, Baltistan, Pakistan.

Image credit:mineralmasterpiece

 

 

Orange Garnet – Spessartite

The light and bright orange-yellow stones come from Nigeria and Ramona (CA). The deeper reddish orange stones also come from Nigeria. The fabulous tangerine orange “mandarin” garnets come from Namibia.

The 3 important sources of spessartite garnets are Nigeria, Namibia, and The Little Three Min at Ramon, California, USA. Most sources produce clean spessartites except from Namibia, which often contain inclusions that give the stones  sleepy appearance.

Most spessartites are in ovals, cushions, trillions and emerald cuts. Cabochon cuts are seen occasionally, more with the Namibians, which tend to be heavily included.

From left to right, the sleepy mandarin garnet from Namibia, the bright orange-yellow spessartites from Nigeria and Ramona, CA.

Image credit: Wimon Manorotkul 

 

 

 

Spessartite can range from pale yellowish orange through bright orange to dark brownish red. The best color is “aurora red” – highly saturated slightly reddish orange in medium to medium-dark tone. This color is often referred to as mandarin orange in the trade.

Very dark or very light tone is less valuable. Large fine quality stones are priced high because while new finds made these orange gems more available, fine quality above 5 carats remain rare.

Here’s a few generalizations on the price of spessartites from palagems.com:

• Nigerian spessartites typically retail for $100–250 per carat (1 – 4 carat range). Stones of 15–20 carats may reach as much as $900 per carat at the retail level.
• Prices for the rare mandarin spessartites from Namibia are even higher, with smaller goods (1–2 carats) fetching up to $800 per carat. Fine stones above 5 carats extend well above $1000 per carat. A large fine fine mandarin garnet was said to be priced for retail at $2400 per carat.

 

Here is a sample of Nigerian spessartite garnets with the most expensive red-oranges at the right.

Image credit: Wimon Manorotkul  

 

 

New sources of spessartite made it available for use as an alternative to other strongly colored gems.

 

Orange Garnet – Malaya

Image credit: Gemselect

The search was meant for rhodolite at Tanzania’s Umba River Valley in the 1960s … but the pinkish to reddish orange Malaya was uncovered as well.

To date, this region between Kenya and Tanzania remains the primary source for malaya. Production and mining has been irregular since its first discovery. Because of its rarity, Malaya is highly prized by gem collectors. Larger specimens, especially over 3 – 5 carats command quite a premium price.

Malaya in Swahili words mean “out of the family” or “outcast.” When it was first found, local dealers rejected it. Thanks to a few knowledgeable American and German dealers who bought and marketed it. By 1980s, malaya found its small but strong followers in the gem market.

Malaya is a mixture of 2 common species: pyrope and spessartite. Not easy to find are beautiful honey-peach, cinnamon, and pinkish orange. A well-balanced bright and peachy color, known as Imperial Garnet, and pinkish-orange specimens are more valuable and well sought-after than the sun-kissed orange to reddish specimens. The rosy shades are very popular, especially in round facet cuts.

Malaya is known to exhibit scintillating brilliant flashes of red, which no other variety of garnets could compare. Like all other garnets, it is naturally included, never treated or enhanced in any way. The needle-like inclusions typically do not affect the value or beauty.

 

Orange Garnet – Hessonite

 

Image credit: John J Bradshaw

Hessonite is a variety of the grossularite species family. Hessonite’s color ranges from orange to cinnamon, and it tends to have a brownish hue. Sometimes referred to as the “cinnamon stone.” Very light orange ones is sometimes called champagne garnet.
The best colors come in medium to dark tones.

Hessonite does not have much presence in the jewelry market because it is too included with crystals to be used as a jewelry. Under the microscope, the recognizable “heat wave” or “scotch-in-water” effect that’s characteristics of hessonite can often be seen (see below picture).

Image credit; Tino Hammid

Originally from Ceylon/Sri Lanka, it is still the largest producer of fine quality hessonite. Mexico also produces good quality strong orange color hessonite. A good quality eye clean hessonite can fetch USD20 – 50 per carat.

Green Garnet – Tsavorite

Image credit: GIA

In honor of where it was found in the 1967, tsavorite was named after the Tsavo National Park, on the border of Tanzania and Kenya. Today, most tsavorite comes from these East African countries – Tanzania, Kenya and Madagascar.

Tsavorite’s irregular rough in potato-like nodules is almost always fractured, yielding only small sizes suitable for calibration under 1 carat. Since large tsavorite rough is extremely rare, there’s a huge price hike between small and large fashioned stones.

A variety of the grossularite mineral species (which hessonite is also a member), tsavorite is today’s most important green garnet.

Tsavorite is highly desirable for its color. The highest values are placed on strongly saturated bluish-green to green gems of medium to medium-dark tone. Yellowish green is less valuable. Lighter tones or lesser saturation do not qualify as tsavorite; they would merely be sold as green grossularites.

A finished tsavorite’s depth of color often depends on its size. All the gems shown in the picture including the 23.23 carat stone (far left) are fashioned from the same piece of rough.

Tsavorite has other appealing properties that make it an attractive and effective less-expensive alternative to emerald. Comparatively, it’s less included. It’s as hard as emerald, thus well-suited to the popular “invisible setting.” It’s rarely treated and owing to its great brilliance, it’s good partner to match the classics: diamond, ruby and sapphire.

All factors equal, carat weight matters. Cut is a consideration in a carat or less. It is, however, of lesser importance in larger stones that have superb color and clarity. Besides, if there are tsavorites that are 2 – 3 carats or more, they would have been sold to informed customers as beautiful gems in their own right. Not just as emerald alternatives.