GEMOLOGY

History and Science of Gemology

Gemology as a Science

Gemmology is the study of Natural gemstones and considered as a branch of Mineralogy. Education in gemmology for jewellers began with British Gemmological Association, founded in 1908 as the Educational Committee of the National Association of Goldsmiths of Great Britain (NAG). NAG set up a Gemmological group for serving the jewellery trade, who then founded the Gemmological Association of Great Britain (Gem-A), as an educational charity and accredited awarding body with its high standards diploma courses taught worldwide. The FGA and DGA initials are prestigious status designations restricted only to holders of Fellowship Diploma in Gemmology and Post Diamond Diploma of the Gemmological Association of Great Britain.

The first US graduate of Gem-A's Diploma Course, in 1929, was Robert Shipley, who later established both the Gemological Institute of America (GIA) and the American Gem Society (AGS).

The first gemological laboratory serving the jewelry trade was established in London in 1925, prompted by the influx of the newly developed "cultured pearl" and advances in the synthesis of rubies and sapphires (synthetics). There are now many professional gem laboratories around the world requiring ever more advanced equipment and experience to identify the new challenges - such as treatments to gems, new synthetics, and other new materials. Gemstones are categorized based on their crystal structure, specific gravity, refractive index, and other optical properties, such as pleochroism. The physical property of "hardness" is defined by the Mohs scale of mineral hardness.

Gemologists study these factors while valuing or appraising cut and polished gemstones. Gemological microscopic study of the internal structure is used to determine whether a gem is synthetic or natural by revealing natural fluid inclusions or partially melted exogenous crystals that are evidence of heat treatment to enhance color.

The spectroscopic analysis of cut gemstones also allows a gemologist to understand the atomic structure and identify its origin, which is a major factor in valuing a gemstone. For example, a ruby from Burma will have definite internal and optical activity variance when compared to a ruby from Mozambique. 

Gemologists use a variety of tools and equipment which allow for the accurate tests to be performed in order to identify a gemstone by its specific characteristics and properties.

• These include: Corrected 10X Loupe, Microscope, Refractometer, Polarizing Filter, Magnifying Eyepiece, Contact Liquid for RI (Refractive Index) up to 1.81
• Polariscope, Optic Figure sphere, Dichroscope, Spectroscope (Handheld or Desktop)
• Penlight
• Tweezers
• Stone Cloth
Additional Tools such as a color filter, immersion cell, UV Light can also be helpful.

Jewellery

Jewellery may be made from a wide range of materials, but generally for our purposes, we consider some quality of precious metal and precious or semi precious gemstones to be set in a piece. Gemstones and similar materials such as Diamonds, Rubies, Sapphires, Emeralds, and Tanzanite, to name a few, are widely used, and enamel has often been important in antique or vintage pieces. In most cultures jewellery can be understood as a status symbol, for its material properties, its patterns, or for meaningful symbols. Jewellery has been made to adorn nearly every body part, from necklaces, to rings, to bracelets. One can learn a lot about the importance and value of fine Jewellery by studying the Crown Jewels of the most powerful empires in history.

Jewellery appraisals are an important reference, documenting the color, clarity, cut, and carat weight, along with the type and purity of precious metal used. The items condition and whether it is accompanied with any Lab Certification also helps the reader understand the importance and collectability of a given piece. Jeweller appraisals are for Retail Replacement for Insurance purposes; such an item may sell for an amount different than its appraisal valuation. 

Gems

Gems • Group of precious and semiprecious stones (both uncut and faceted) including diamonds, uncut synthetic sapphires, rubies, uncut emeralds, and amethyst crystal clusters.

Gemstone • a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, and jade) or organic materials that are not minerals (such as amber, and pearl) are also used for jewelry and are therefore often considered to be gemstones as well. Most gemstones are hard, but some soft minerals are used in jewelry because of their luster or other physical properties that have aesthetic value. Rarity is another characteristic that lends value to a gemstone. 

Diamonds

Diamonds • known as the hardest natural substance, and are rated 10 out of 10 on Mohs hardness scale, which ranges from 1 for very soft materials, to 10 for the hardest. Their hardness, coupled with their rarity, beauty, and resilience makes diamonds the most alluring of all gems. While all classic gems can be valuable, Diamonds are the ones that are considered as the top choice as a store of wealth.

Since Diamonds form around 100 km below the surface of the earth under extremely high pressure and temperatures, it takes millions of years for them to surface by naturally occurring geological events such as volcanic eruptions. Colorless Diamonds are pure carbon, with a very tightly packed and rigid structure, forming strong bonds with other carbon atoms.

Pictured • Natural Rough Diamond crystal & Faceted Round Brilliant Cut Diamond

Shape • After mining, Diamonds can be cut and polished into many different shapes, including Round, Heart, Pear, Marquise, and Princess Cuts to name a few. Cutting is a painstakingly challenging process, where the approach has to be planned carefully so as to maximize weight yield, and beauty in the finished product.

Pictured • A lineup of rough Diamond crystals, with a Fancy Reddish Brown Round Cut Diamond in tweezers.

The Four C's

Carat

1 Carat is the weight unit used for gemstone, which is equal to 1/5th of a gram. The higher the Carat weight of a Diamond, the higher the price per carat. 

Color

Diamonds are graded on a scale of rare category of completely colorless to those showing more body color. The color grading scale was introduced by the Gemological Institute of America (GIA).

Diamonds graded at top of the color scale are void of any color tone, are rare, and highly valued. The higher the color grade, the higher the price it commands.

Clarity

GIA has also introduced a clarity grading system, which ranges from rare perfect grades (Flawless) to those with increasing amounts of impurities trapped inside the Diamond. These impurities are called Inclusions. Higher clarity Diamonds command a higher price.

Cut Grade

GIA has introduced several grades for cutting and finishing of a Diamond. Well cut gems that have maximum light return, and are close to Ideal proportions are graded as Excellent. The Cut from there goes to Very Good where the cutter reached a result that is slightly below the Ideal proportions, and from there, we go down to Good, Fair, and Poor. Again, the value starts to drop as we move down the Cut Scale.

Rubies

Rubies • Rubies are 8 out of 10 on Moh’s hardness scale, and have always been the perfect romantic gift but their rich colour not only signifies passion, but also wealth and success. The redness of a Ruby has the biggest influence on price. Rubies prices are based on their origin, color tone, as well as their size. Unheated Rubies command a strong premium. Certain mine locations are considered more collectable than other, and are priced accordingly.

Sapphires

Sapphires • Sapphires are also 8 out of 10 on Moh’s hardness scale and have long been connected with royalty and the elite throughout history. Most Sapphires are heat treated, with unheated examples leading the price charts due to scarcity. Sapphires come in full range of colors. The origin of a Sapphire can influence the price greatly. For example, Kashmir Sapphires are highly sought after due to their velvety blue appearance, and scarcity. Sapphires are judged based on fine color, size, and clarity, with unheated examples from important origins leading the price charts.

Pictured • An Ultra Fine Unheated Purple Sapphire & Diamond Ring

Emeralds

Emeralds • Emeralds belong to the Beryl family of minerals, which also include Morganite and Aquamarine. Emeralds are quite resilient, with a Mohs hardness of 7.5-8. Most Emeralds are oiled, which is an acceptable treatment in the gem trade, and helps to improve the clarity of the gemstone. Origin of an Emerald also dictates price, however, fine examples from just about any country are considered rare and important.

Pictured • Fine Emerald & Diamond Ring

Handcrafted Fine Watches

A watch is a timepiece intended to be carried or worn by a person. It is designed to keep working despite the motions caused by the person's activities. A wristwatch is designed to be worn around the wrist, attached by a watch strap or other type of bracelet. A pocket watch is designed for a person to carry in a pocket.

Fine collectible watches, valued more for their elaborate craftsmanship, aesthetic appeal and glamorous design than for simple timekeeping, often have traditional mechanical movements, even though they are less accurate and more expensive than electronic ones. Various extra features, called "complications", such as moon-phase displays and the different types of tourbillon, are sometimes included.

Modern watches often display the day, date, month and year. In appraising watches, we look for hallmarks, precious metal stamps, reference or model numbers to identify and certify a watch. Most fine watches are hand crafted in Switzerland, such as Rolex, Patek Philippe, and Audemars Piguet to name a few, and are marked with a “Swiss Made” stamp on the dial. There are however, proud and established watch making traditions in Germany, producing quality timepieces such as Glashutte, and A. Lange. A watch appraisal serves as a certified, independent analysis, documenting watch images, condition and other important features such as limited editions, and whether it is accompanied with a box and certificate. Watch appraisals are for Retail Replacement for Insurance Purposes, and do not reflect what an item would trade for on a given day.

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