What is a Gemstone?
Gemstones are pieces of mineral crystal that are used for decorating jewelry and other items. Certain rocks and organic materials that are not minerals are also sometimes used and are regarded as gemstones as well. These gem materials are chosen for use in jewelry manufacturing and other adornments due to their outstanding beauty, rarity, and durability. However, the faceted gems that you see in fine jewelry have usually been cut, polished, and occasionally treated to enhance their appearance. Thus, they often look very different from the natural stones that were mined.
Gemstones come in a variety of different colors. Indeed, the names of several precious gems are also used as adjectives for a particular color. For example, emerald, turquoise, and aquamarine all refer to a particular shade of green or blue.
Gemstones also differ in terms of their physical properties and resistance to scratching, which is measured on the Mohs Scale for mineral hardness. The scale runs from 1 to 10, with 1 representing the softest mineral and 10 the hardest. While most precious stones are hard, others are too soft and fragile to be used in jewelry making. Instead, these softer gemstones are sometimes displayed in museums or collected by precious stone collectors.
Given that there are so many gemstone types to choose from, it can be challenging to decide which one is best for you. Below, we have compiled a list of gemstones with some important facts about each one to help you make an informed buyer’s decision.
LIST OF COMMON GEMSTONES
Here is a brief introduction to some of the most popular gemstones on the market and the ones that are available at ICONIC.
Hardness: 10 (extremely hard)
Though often treated as a separate category of popular gemstones, diamonds are, in fact, a type of precious gem. Uniquely strong and brilliant, diamonds symbolize eternal love and are the most popular gemstones for engagement rings. The word “diamond” stems from the ancient Greek word “admas”, used to describe something that is unbreakable or invincible.
Most of the diamonds available on the market are white diamonds, which are prized for their brilliance. However, black diamonds are slowly becoming more popular, and fancy-color diamonds also appear in gemstone jewelry from time to time, though these are extremely rare. To learn more about diamonds, visit our Diamond Education section.
Anniversary: 10th, 60th
Hardness: 7.5-8 (medium-very hard)
The gem of spring, emeralds symbolize rebirth. The ancient Egyptian queen renowned for her exceptional beauty, Cleopatra was known for her affinity for these radiant green gems.
Emeralds are a type of beryl that belongs to the same mineral species of colored gemstones as aquamarine. Thus, the color range for emeralds is not limited to green colors since gems that exhibit a greenish-blue hue are also considered acceptable. Color is, however, the single most important factor in evaluating emeralds, and the more intense and vibrant the color, the greater the value of the gem.
Emeralds are also one of the most unusual gemstones since they are rarely eye-clean and almost always have visible inclusions (referred to as “jardin”). The presence of these imperfections usually reduces the value of any other gem but are considered acceptable for emeralds in their polished form.
Anniversaries: 20th, 35th
Hardness: 9 (very hard)
Referred to as the “king of gems”, rubies have been known as the gemstone for centuries. As a variety of the corundum mineral species, rubies can sell for the highest price per carat among all the other colored gemstones.
A ruby’s color ranges from red to orange-red or purplish-red. As a result, rubies are often heat-treated to intensify their color and improve clarity. They also appear a deeper red under incandescent light.
With a name stemming from the Latin word for red (“ruber”), this fiery dark-red crystal symbolizes love and passion.
Anniversary: 15th, 40th
Hardness: 9 (very hard)
With a name that comes from the Greek word for blue (“sappheiros”), you may be surprised to learn that sapphires are available in a variety of rainbow colors. Besides blue, popular colors for sapphire stones include pink, yellow, and white.
Known as the gem of truth and fidelity, the blue sapphire is among the most popular gemstones for engagement rings. Princess Diana was one of the most famous wearers of a sapphire engagement ring. It’s the very same ring now worn by the Duchess of Cambridge.
As with other popular gemstones like rubies, sapphires are often heat-treated to enhance their color and clarity.
Anniversary: 5th, 45th
Hardness: 10 (extremely hard)
A black diamond is a very unique and beautiful gem variety. Bold and mysterious, black diamonds make a statement, especially when paired with white diamonds or a minimal setting.
In nature, black diamonds get their color from the presence of dark inclusions. However, most black diamonds that you see have been heat-treated. The treatment turns any dark green inclusions in the stone darker – to the point where they appear black.
Hardness: 7 (medium hardness)
Found in a variety of purple hues, amethyst is the most valuable variety of the mineral quartz. Throughout history, this semi-precious gem has been considered the stone of sobriety (Ancient Greece), love (Middle Ages), and intellect (Renaissance). St. Valentine is believed to have worn an amethyst ring engraved with the image of Cupid.
Prior to the discovery of large amethyst deposits in the 19th century, this purple gemstone was considered one of the rare gemstones and was worth as much as a ruby. Today, amethyst is more affordable but is still counted among the popular gemstones.
Anniversary: 6th, 17th
Hardness: 7 (medium hardness)
Citrine is a warm, yellow-toned variety of quartz. This semi-precious gemstone is often confused with topaz since the two gemstones are both birthstones for November, just like tanzanite, turquoise, and zircon gems share the status of being birthstones for December.
A natural yellow citrine is very rare. Most citrine gems that you see are the product of heating amethyst, another variety of quartz. The color of the finished gem can range from pale yellow to orange-brown.
Among the most popular semi-precious gemstones, citrine is sometimes referred to as the “merchant’s stone” or the “money stone”, as it is believed to bring good luck and prosperity to its wearer.
Hardness: 8 (very hard)
Topaz is another one of the popular gemstones used in jewelry making. It exists in various shades of brown, yellow, green, blue, red, pink, orange, and purple. Colorless specimens are also quite common and have occasionally been mistaken for diamonds.
Blue, the most popular color for topaz, is actually the rarest. The blue color is the result of irradiation and heat treatment in a lab. These treatments turn colorless or pale gems into beautiful shades of blue, such as Swiss (a light blue) and London blue (a deeper blue, almost dark blue).
Birthstone: November (precious topaz), December (blue topaz)
Anniversary: 4th (blue topaz), 23rd (imperial topaz)
Hardness: 6.5-7.5 (medium hardness)
Garnets come in a wide range of colors, but the red garnet is the most well-known among the different varieties. Fiery and intense, this stone has been popular for millennia. We know this because archaeologists have discovered garnets in jewelry dating back over 5,000 years. Garnet stones are also steeped in myth and were once thought to protect travelers from harm. For example, in the story of Noah’s Ark, Noah reportedly used a garnet lantern to light the way.
Non-red varieties of garnet gems include green Russian demantoid (first discovered in Russia’s Ural Mountains and the rarest and most valuable of the January birthstones), African tsavorite, pink and purple rhododendron, orange or reddish-brown spessartite, and hessonite.
Hardness: 7 (medium hardness)
Onyx is a banded variety of the mineral chalcedony. The ancient Romans and Greeks often used it for producing cameos and wax seals due to its ideal texture for carving.
Today, most of the onyx used in jewelry comes in several shades of black, white, or red, in which case it is called “sardonyx”. Most black-colored onyx is the result of chemical treatment, a common practice used for thousands of years. One technique that was used in ancient times, described by the Roman philosopher Pliny the Elder in the first century, included soaking the gem in sugar water. The glossy noir style of a beautiful black onyx is perfect for art deco-style designs or used to contrast white diamonds.
Hardness: 6.5-7 (medium hardness)
Called the “gem of the sun” by the ancient Egyptians, peridot is one of the few gemstones to exist in only one color: green. Vivid lime green is the most desirable color for these gems, though their color ranges from yellow-green to green tinged with brown.
Typically formed in the heat and pressure of the earth’s mantle, peridot gems also exist in outer space. We know this because peridot crystals have been found in pallasite meteorites. However, gem-quality peridot is quite rare, and it is often displayed in museums or used for scientific study.
Birthstones: Names of gemstones for each month
January : Garnet
February : Amethyst
March : Aquamarine
April : Diamond
May : Emerald
June: Pearl or Alexandrite
July : Ruby
October: Tourmaline or Opal
November : Topaz or Citrine
December : Tanzanite, Zircon or Turquoise
Frequently Asked Questions
Tanzanite—$1,200 per carat
Black Opal—$9,500 per carat
Red Beryl—$10,000 per carat
Musgravite—$35,000 per carat
Alexandrite—$70,000 per carat
Emerald—$305,000 per carat
Ruby—$1.18 million per carat
Pink Diamond—$1.19 million per carat
Jadeite—$3 million per carat
Blue Diamond—$3.93 million per carat
Ruby – Known as “the king of gems”, ruby is renowned for its brilliant red hue.
Sapphire – Contrary to popular belief, sapphires come in a range of colors besides blue. These are known as fancy-color sapphires and include the popular “ruby sapphire” (pink), orange, yellow, green, and purple.
Emerald – The most desirable hues for emerald are blue-green to pure, vibrant greens with no darkness or yellowing in the stone at all – just evenly distributed colors that give off a brilliant glow when the stone has been polished to resemble glass.
Pearl – Pearls are among the most beautiful gemstones in existence, being prized for their iridescent sheen. They come in a range of colors, including white, yellow, cream, brown, black, and gray.
Amethyst – Amethyst is a variety of quartz. Its color varies from light purple to nearly black. Siberian amethyst is the rarest gemstone of its type, featuring a rich purple hue.
Quartz – Quartz is a crystallized mineral composed mainly of silica. Popular gemstones that belong to the quartz variety include citrine, which comes in shades of light to dark yellow, orange, and brown; amethyst, characterized by its range of purple hues; and rose quartz, which is easily recognized by its pale pink color.
Tourmaline – Tourmalines come in a range of colors, including green, blue, and yellow. Pink tourmaline is colored by the trace element manganese, while brownish-yellow stones are called dravite, and black ones are known as schorl (a type of black geode).
Citrine – Citrine colors range from light yellow to dark orange and brown. However, high-quality citrine gems have an intense golden hue, with fiery orange flashes inside. These gems can be transparent or cloudy, depending on their origin. Another color variation prized among citrines is a deep red free of brown tints. Gems that exhibit this coloration are called Madeira Citrines since they bear a strong resemblance to the wine made from the fruit grown on the Portuguese island.
Peridot – These unique gemstones are a variety of the mineral olivine. They only come in one color, namely green, but the intensity and hue can differ for each stone. Thus, peridot gems can exhibit many different shades of green, with some appearing more yellow than others.