Why are some stones worth of the title gemstone, while others are just precious stones or even worse rocks?
Since ancient times, many materials have been set in jewelry. Over the centuries though the term gemstone has come to mean a naturally occurring mineral desirable for its beauty, its rarity and durability.
Gems are diverse in their beauty. Diamonds have a fiery brilliance, pearls a soft iridescence and many gemstones occur in a stunning variety of colors. The source of the gemstone’s beauty though is light. The interactions between the minerals in the gemstone and light cause the intense colors of some stones and the amazing play of colors in others.
Most gemstones have little beauty in the rough state. They may look like ordinary rocks or pebbles. It is not until a skilled cutting and polishing by a lapidary, that the full color and luster of that stone can be seen. This is never more noticeable than in the diamond. The diamond’s magnificent fire is displayed in a precise cut to show off the stone’s natural inclinations.
The rarity of a stone imparts a sense of exclusiveness and worth that increases our desire to possess it. Rarity determines the prices placed on gems and famous jewelry the world over. Gems may be rare for a variety of reasons. Many gems are varieties of common stones, but their exceptional color or clarity determines them to be rare gemstones. Quartz and feldspar are stones that make up two-thirds of the Earth’s crust in a common gray or cream color. Very little quartz is amethyst with its gorgeous purple color and little feldspar display rainbow iridescence like the labradorite feldspar. A few gem minerals are rare due to occurrence. One such gem is the diamond, which are 5 grams to every 100 tons of kimberlite, the host rock. Other gems contain rare chemical elements such as beryllium in taaffeite and emerald. In few gems these qualities are combined with a very large size. For example the Cullinan diamond weighed 3,106 carats in its rough state.
Gems manage to endure through time because they are resistant to chemical alteration, are hard enough to retain a good polish and are not easily chipped or broken. Hardness is the measure of a gemstone’s resistance to abrasion. To wear well a gemstone must be tough. Despite being harder than quartz, emerald is brittle and chips easily. Diamond and topaz break along planes of weak atomic bonding if dropped or knocked against hard objects.
Now that you know all about gemstones , stop by Gems Explained to learn about types of gems, their cuts and locations.