Gems TV

UNDERSTANDING GEMSTONES

The beauty, rarity and historical mystique of gems are timeless. Their richly diverse varieties and colours come in a kaleidoscopic array. However, before you make a purchase, you will need a basic understanding of gems.

Understanding and appreciating the value of gems is essential to making a successful and rewarding purchase. Regardless of the gem variety you’re buying, there are a few constant rules to bear in mind.

What is a gem?

For decades, the Gemmological Institute of America (GIA) has taught their students that “gems are specimens of minerals (most gemstones are generally solid crystalline minerals formed by the earth’s geological processes) or organics (materials formed by organic life processes, e.g. Pearls and Amber) used for personal adornment that possess the attributes of beauty, rarity and durability”. The GIA states that all three of these attributes must be present - a gem lacking in one or more of these attributes risks losing its status as a gem.

You may have heard about the 4 C’s related to valuing gemstones: colour, cut, carat weight and clarity. While gemstone professionals and connoisseurs the world over rely on these factors, we’ll also cover other elements that also need to be taken into consideration when purchasing coloured gemstones.

Colour

Understandably, colour is the single most important factor when evaluating coloured gems. Generally, the more attractive a gem’s colour, the higher the value. Bright, rich and intense colours are generally coveted more than those that are dark or light. However, there are exceptions such as Morganite and Rose de France Amethyst. Although specific colour hues can affect the prices of gems, as colour is subjective, personal preferences are also very important. The colours seen should ideally remain attractive regardless of prevailing light conditions. Whether viewed indoors, outdoors, by day or by night, a gem should always remain beautiful.

The mixing of colour hues into combinations, such as violet-blue in Tanzanite and bright blue-green in Apatite is attractive and value-enhancing. Many gems also have specific expressions to denote the very top colours found within a species (e.g. Cornflower Blue Sapphire). Such terms relate to the most desirable colours to be found within a gem species.

The elements that give most gemstones their colour are termed “idiochromatic” (self coloured) if the colour results from a colouring element that is always incorporated into the crystal structure or “allochromatic” (other coloured) if the colour results from trace elements that are not part of the normal crystal structure. However, colour in some gemstones, such as Coloured Diamonds and Blue Topaz, are caused by “colour centres”. These are imperfections in the crystal lattice that cause colour by absorption of light.

Cut

Unlike Diamonds, coloured gems possess variable optical properties and are not cut to a uniform ideal. A well-cut coloured gem exhibits even colour, an acceptable number of inclusions for the type, good brilliance and shows the majority of carat weight when viewed from the top. As gemstones are nature’s creations, cutting is often a juggling act between carat weight retention and beauty.

Broadly, the styles of gem cutting can be divided into faceted gems (gems with geometrically-shaped flat polished faces) and non-faceted gems (those gems that do not have geometrically-shaped flat polished faces such as cabochons).

Carat weight

Gemstone weight is measured in carats. This archaic unit of measurement originates from the traditional use of carob seeds to weigh gems in the bazaars of the Middle East and Asia. Carob seeds were used because of their consistent size and shape. In 1907 in Europe and in 1913 in the US, carat weight was standardised as one fifth of a gram (one carat is the equivalent of 0.20 grams). Gemstones less than 1 carat are often measured by dividing the carat weighed into 100 smaller units known as points. For example, a 50 point gemstone can also be described as half a carat and a 25 point gemstone can also be described as a quarter of a carat.

The term carats is often confused with “karats”. Karat is a measurement of gold purity and has no relationship to the term carats, other than the fact that they both originate from the use of carob seeds, which in this case was used to weigh the alloys added to gold.

Generally, as the weight of a gem increases, so does its price per carat. Large gems are always rarer than smaller ones, so per carat prices rise exceptionally. For example, a 3 carat Ruby is always worth far more than three 1 carat Rubies of the same quality. The only time the combined weight of smaller gems costs more than a singular gem of the same carat weight is when the labour cost of applying all the facets to the individual gems outweighs the difference in price.

Gemstone prices also increase rapidly when in excess of certain key weights. For example, a 2.01 carat Ruby has a higher price tag than a 1.99 carat Ruby, despite a negligible difference in actual size. Gem pricing is therefore based on a “nonlinear scale of increments”. To put this into context, a 16 carat Ruby sold at Sotheby’s in New York in October 1988 for a staggering $3,630,000! If gem pricing was linear, that would make a similar 1 carat Ruby worth $226,875.

As gemstones are nature’s creations, no two gemstones are absolutely identical. Therefore, the gem weights specified on the GemsTV certificate of authenticity is the MTGW (Minimum Total Gem Weight) used to create each jewellery design. Each specific handcrafted piece will most likely contain a higher gem weight.

If you are buying a gem with a rounded carat weight, make sure that the quality of the cut (i.e. beauty) has not been compromised to achieve a larger carat weight, as a reduction in beauty might reduce the value of the gem.

Clarity

Often adding character and individuality, most gems contain tiny natural features called inclusions. Mostly microscopic in nature, they are most easily glimpsed under magnification. Inclusions are a fascinating hallmark of authenticity that record a gem’s natural relationship with the earth.

The clarity of gems is determined by judging the amount and location of inclusions that can be seen. Basically, the higher the clarity grade, the higher the value of the gem. In general, inclusions that don’t interfere with the brilliance, sparkle and fire of a gem don’t affect the value. In some cases, inclusions can even increase a gemstone’s beauty and value (e.g. asterism or the star effect).

In transparent gems, the degree of transparency and light return (brilliance) is considered crucial. However, through market experience, we learn to expect certain degrees of clarity from certain gems. For example, Aquamarine is generally expected to be clean with no inclusions while Emerald is generally expected to have inclusions.

Country

The fifth C is “Country” of origin. Names of geographical locations should only be used when they denote the areas from which gemstones originate (for example, it is misleading to call a high quality Amethyst “Siberian” if it doesn’t actually come from Siberia).

While there are exceptions, gemstones that are rich in history and folklore are generally more prized than those lacking historical connotations.

When specifying an origin, GemsTV undertakes a series of checks based on our experience to ensure that a gemstone displays the characteristics indicative of the origin specified. While GemsTV does everything possible to ensure that the origins we specify are correct, gemstone origin is considered a matter of opinion.

Conflict free

The sixth C is “Conflict” free. Any Diamonds purchased from GemsTV have been sourced from legitimate traders not involved in funding conflict and in compliance with the United Nations Resolutions (the Kimberley Process). You can learn more about the Kimberley Process here or by visiting www.DiamondFacts.org.

Based on personal knowledge and/or written guarantees provided by our suppliers, GemsTV guarantees that our gemstones have been purchased from legitimate sources not involved in funding conflict or terrorism.

Durability

“The love of precious gemstones is deeply implanted in the human heart,” George Kunz wrote in his book “The Curious Lore of Precious Stones”, “The cause of this must be sought not only in their colouring and brilliancy but also their durability”. Kunz further wrote, “The sheen and colouration of precious stones are the same today as they were thousands of years ago and will be for thousands of years to come. In a world of change, this permanence has a charm of its own that was early appreciated”.

A gemstone must be durable enough not to break or fade over years of wear. Its brilliance and beauty are expected to last for a very long time, even to the point where a gemstone will outlast its owners and be passed on to sons and daughters, who, in turn, will help maintain its status as a gem, by awakenong appreciation in succeeding generations. While gems with better durability and resistance to wear are generally more highly prized than those of lesser durability, given proper care, all gemstone jewellery should be suitable to be passed down to many generations.

Durability is a combination of 3 properties:

Rarity

By their very definition, all gems are rare. Rarity can be described in three, often unrelated, ways:

While scarcer gems are generally more highly prized than less scarce varieties, geological rarity doesn’t always mean a gem has a higher value in the marketplace and vice versa. Beauty and marketing play a big part. Sometimes the geological rarity of a gem type jeopardises commercial viability. Tsavorite Garnet is rarer than Emerald, and is frequently more beautiful, but because of its rarity, it cannot compete with Emerald in terms of the consumer perception of its value. Given the enormous Diamond stockpiles and new sources springing up around the world, when compared to many coloured gemstones, Diamonds are not especially rare. Strict control of polished Diamonds on the market, combined with sophisticated consumer advertizing, has elevated Diamonds to the extent that they are perceived as a rare and coveted product.

If a gem variety is so rare that it is essentially unknown to the general public, it is often classified as an “exotic gem”. Gems such as Boracite, Childrenite and Simpsonite are extremely rare, attractive and durable, but they are unlikely to command prices appropriate to their rarity because few people are aware of their existence.

Pairs and suites

Pairs or suites of gems matched for colour, clarity and cut are valued more highly per carat or per gem than single gems of the same quality. Given the rarity of many gems, a matching set is disproportionately hard to find and will command a higher per carat price than if each of the gems from the suite were sold separately.