Bohemian Garnets

This Brooch Dates From the Third Quarter of the 19th Century. (Photo Courtesy the National Czech & Slovak Museum & Library)

This Brooch Dates From the Third Quarter of the 19th Century. (Photo Courtesy the National Czech & Slovak Museum & Library)

“Bohemian garnets” are garnets mined in an area once known as Bohemia (it often refers to the entire Czech territory, including Moravia and Czech Silesia). They are the variety of garnet called pyrope (from the Greek words pyr for “fire” and ops for “eye”). Those found in Central Bohemia (in the north of the Czech Republic) are considered to be of the highest quality. 
The Bohemian garnet has been mined for over 600 years mostly dug at the mines of Meronitz, and chiefly in the northwestern part of the Czech Republic. The garnets are found in a gravel or conglomerate, resulting from the decomposition of a serpentine. Sometimes, however, they are found in the matrix. When this happens they are often associated with a brown opal. Most of the good quality the stones are small with those as large as approximately 1/4 inch and above being reported rarely. By the 19th century it was determined that the elements creating the intense red color in pyrope were Chromium and Manganese. The color ranges from fiery-red to ruby-red. The Bohemian garnet also possesses excellent clarity, transparency, and has a high refraction of light. This means that the stone has a remarkable sparkle and what has been described as an "inner glow".

The stone gained popularity in Europe in the 18th and 19th century also becoming a favorite of the Victorians. Traditional Bohemian design placed it's emphasis on the arrangement of the garnets, taking precedence over the metal chosen for a piece of jewelry. George Frederick Kunz cites in his book Rings for the Finger Garnet that rings were generally made of faceted, rose or cabochon cut Garnets in 14 or 18 kt gold. By the late 19th century larger Pyropes were typically brilliant-cut, resulting in very bright (red) stones, whereas the very small stones were usually rose-cut. 

This Art Nouveau Style First Appeared in Individual Creations of Designers Rather Than in Industrial Mass Production. (Photo Courtesy The National Czech & Slovak Museum & Library)

An Example of the Mass Produced Items Typical of the Bohemian Garnet. (Photo Courtesy The National Czech & Slovak Museum & Library)

An Example of the Mass Produced Items Typical of the Bohemian Garnet. (Photo Courtesy The National Czech & Slovak Museum & Library)

The introduction of larger scale manufacturing of garnet jewelry created mass-produced machine pressed metal settings and garnets of inferior quality. The majority of readily available "Bohemian Garnet" antique jewelry falls into this mass production category. While these pieces are beautiful in their own right, it should be noted that like any piece of jewelry rarity and individuality are valued much more highly. 

Antique Pyrope Hairpin From the Smithsonian


Turquoise: The Desert Beauty

The most traditional birthstone for the month of December is Turquoise and  the zodiacal stone for Sagittarius. Opaque, varied blue colors that has been used for centuries in jewelry and in decorative ornaments.

If cold December gave you birth,
The month of snow and ice and mirth,
Place on your hand a turquoise blue;
Success will bless whate'er you do.

Turquoise is found in various locations around world that all share the same characteristics: dry, arid, barren and possessing acidic, copper-rich ground water. This ground water creeps downward it reacts with other minerals. The product of this process is the compound of hydrated copper and aluminium phosphate known as turquoise.

The deposits of turquoise usually form in iron-rich limonite or sandstone. The remnants of these host minerals (called the matrix) are what leave the veins or splotches on the turquoise. (Limonite creates the darks brown markings and the sandstone creates tan markings)
The texture of turquoise is a result of both its structure and composition. If you look at turquoise under a microscope you may see that it is actually an aggregate of microscopic crystals that form a solid mass. The closer the crystals are packed, the finer the texture and the less porous the material. Fine textured turquoise has a shiny waxy luster when it is polished, while less dense turquoise results in a duller luster.

Turquoise from Bisbee Arizona

Turquoise from Bisbee Arizona

The porosity also affects the stones' durability with the less porous turquoise possessing less toughness. Because of the decreased visual appeal and the lesser amount of durability more porous turquoise is often treated to make it smoother, shinier, and more marketable.

turquoise

                                                                                                                                                                                  Most people will be familiar with vein like black matrix running through the vibrant blues or greens; however, the most expensive and prized turquoise has no matrix showing. The second most valuable is a thin web like matrix that is evenly distributed throughout the stone.This really is personal preference, and some turquoise lovers may find imperfections part of the charm.

Turquoise is very soft, ranking a 5-6 on the Mohs hardness scale. This makes the stone ideal for carving and artists throughout history in Europe, Asia, the Middle East and  the Americas have utilized it as a medium for both jewelry and art objects.

Turquoise has a long and varied history (that continues to this day) of being used as talismans, amulets, or religious artifacts as it has been attributed to have special power and meaning to various cultures. The ancient Egyptians, Meso-Americans, Native Americans and Tibetans have believed in the special powers of turquoise for centuries. Some believed that turquoise can protect its wearer from harm, others thought that it brought good luck or longevity, and some uses and meaning have been lost to history.

                  Egyptian middle Kingdom faiance hippo                                       The MET Mu…

                  Egyptian middle Kingdom faiance hippo
                                       The MET Museum

The high value placed on fine turquoise caused many imitations to be made. The first of which dates back to ancient Egypt: a glazed earthenware material called faience. Later glass, and enamel were used. In modern times plastic, porcelain, composites of minerals were used. In 1972 the closest “synthetic” turquoise was produced by Pierre Gilson. I put synthetic in quotes since it is actually called a simulant owing to its chemical composition differing from actual turquoise due to a bonding agent. The simulated turquoise is available in both fine and spiderwebbed varieties.

The most common natural stone imitators of turquoise that might be encountered are dyed howlite and magnesite. These stones are both white in their natural state and contain black veining.

All of these imitators are fairly easy to identify by a  trained gemologist and many can be identified by the general consumer as well.

Basics:
Chemical Formula: CuAl6(PO4)4(OH)8•4H2O Copper containing basic aluminium phosphate
Hardness: 5 to 6 on the Mohs scale
Formation:Turquoise occurs as botyroidal (grape-like) masses or nodules in fissures.
Found in: Currently the finest quality turquoise is found in Northeast Iran. Major turquoise deposits are also found in Afghanistan, Argentina, Australia, Brazil, China, Israel, Mexico, Tanzania and the USA.