When choosing gemstones for jewelry, the eye-catching color is generally the most notable physical feature. Each stone has a unique crystalline structure and how this composition interacts with light determines the optical properties of each and every gem and the appearance of its color. It is this uniqueness and the organic nature of gemstones that makes them so precious to own.
There are many traditions associated with the usage and giving of gemstones although these can differ by culture and many of their origins are unknown. For instance, many believe that the agate gemstone protects against the evil eye and pearls are for health, wealth and good luck. Whether you are looking for a birthstone piece of jewelry, commemorate an anniversary or add a special splash of color to your wardrobe, take a look at our complete guide of significant gemstones.
WHAT MAKES A GEM …. A GEM?
Gemstones come from many sources and are comprised of different things. A gem can be a rock, a mineral, or organic matter. The main factor in elevating a rock, mineral, or biogenic substance to gemstone status comes down to two fundamental factors: rarity and beauty.
THE PRECIOUS GEMS
The custom of distinguishing between precious and semi-precious began in classical Greece. The gems we recognize today as precious gems are:
The four precious gems share important factors that contribute considerably to their perceived value:
- The precious gems are exceedingly rare
- They are the hardest among gemstones
- They are all translucent
THE SEMI-PRECIOUS GEMS
All other gemstones except precious gems are considered semi-precious stones. However, this is a commercial based classification and was a distinction that marketers created years ago which gives the false impression that precious stones are more valuable than semi-precious stones. For example, a Tsavorite green garnet is more valuable than a mid-quality sapphire. It’s a concept that often puts misconceived notions of the truth into consumers’ minds. So contextually there is a difference between semi-precious and precious but it is mostly for show and strictly from a commercial perspective.
Semi-precious stones include:
- Blue Topaz
- Rose Quartz
- Black Onyx
Gemstones are also characterized by their optical properties such as refractive index (how a gemstone bends light) as well as hardness and toughness. Hardness is expressed numerically from one to ten with one being the softest (talc) and ten being the hardest (diamond). This system of classification is known as the Mohs scale because it was invented by a 19th century geologist named Friedrich Mohs. Hardness refers to a gemstone’s resistance to scratching while toughness refers to its resistance to chipping and breaking.
WHERE DO PRECIOUS GEMSTONES COME FROM?
Significant gemstone deposits have been discovered, explored, and often depleted across the globe. A significant portion of gem mining is artisanal, done by hand without a huge environmental impact. Here is a brief list of geographical locales famous for their gemstone mines:
- Ratnapura, Sri Lanka: Located in the southwest of Sri Lanka, an island off the southern coast of India, Sri Lanka is the origin of the majority of fine sapphires. The gem trade is a huge portion of this country’s economy.
- Bo Rai, Thailand: A major source of sapphires and rubies, the gem trade fueled the economy of this eastern Thailand township until the mines were exhausted.
- Mogok, Myanmar: Formerly known as Burma, 90% of the world’s rubies are mined in Myanmar. The Mogok Township is noted particularly for the color and clarity of its rubies. Most are sold to dealers in Thailand, as the oppressive government runs the mining industry and many other foreign businesses refuse to buy Myanmar rubies due to the deplorable human rights abuses by the military.
- Kimberley, Australia: This region of northeast Australia is home to the Argyle mine, the world’s only source of rare pink diamonds and represents one third of global diamond production.
- Muzo, Coscuez, and Chivor, Colombia: Known as the world’s leading source of emeralds, Colombia is also home to the world’s oldest working gem mines.