Types of Gemstones

In this guide, we explain the symbolic, historical, and practical differences between an array of beautiful gemstones so you can make an informed decision when it comes to buying loose precious stones and gemstone jewelry.


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.



Precious Stones

types of gemstones - diamond, extremely rare gemstone, fine jewelry, mineral quartz, yellow green, mineral beryl, mineral corundum, gem enthusiasts, durable gemstone, synthetic gemstones, lapis lazuli

Diamond

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.

Birthstone: April

Anniversary: 10th, 60th

Gemstones - Emerald, green, organic gemstones, fine jewelry, yellow green, mohs hardness scale, mohs hardness scale, many gemstones, lab created

Emerald

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.

Birthstone: May

Anniversaries: 20th, 35th

Gemstones - Ruby, red tourmaline, cultured pearls, fire opal, optical properties, types of gems, gems types, types of gem, gemstone types, gemstone types, gemstones types, gemstones types, gemstone type

Ruby

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.

Birthstone: July

Anniversary: 15th, 40th

Gemstones - Sapphire, ocean blue, colored stones, violet blue, birth stone, blue zircon, hardest gemstones, kinds of gemstone jewelry, most common gemstones, different types of gemstones, most precious gems

Sapphire

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.

Birthstone: September

Anniversary: 5th, 45th

Gemstones - Black Diamond, very popular gemstone, smoky quartz, only gems, how to choose gemstone, most precious gem

Black Diamond

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.

Birthstone: January

Anniversary: 2nd

Gemtones - Amethyst, deep reddish purple, zodiac stones, long history, rich purple, all types of gemstones, types of gemstone, most precious gemstones, types of precious stones,

Amethyst

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.

Birthstone: February

Anniversary: 6th, 17th

Gemstones - Citrine, yellow gold, light yellow, lemon yellow, ancient greeks,

Citrine

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.

Birthstone: November

Anniversary: 13th

Gemstones - Blue Topaz, different stones, only four precious stones, blue stone

Topaz

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)

Gemstones - Garnet, different stones, semiprecious stones, light pink

Garnet

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.

Birthstone: January

Anniversary: 2nd

Gemstones - Black Onyx, different stones,

Onyx

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.

Anniversary: 7th

Gemstones - Peridot, yellow gemstones, yellow sapphire

Peridot

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.

Birthstone: August

Anniversary: 16th


Birthstones: Names of gemstones for each month

January : Garnet

February : Amethyst

March : Aquamarine

April : Diamond

May : Emerald

June: Pearl or Alexandrite

July : Ruby

August: Peridot

September: Sapphire

October: Tourmaline or Opal

November : Topaz or Citrine

December : Tanzanite, Zircon or Turquoise


Frequently Asked Questions

A gemstone is a mineral crystal or stone that can be cut and polished for use in jewelry or other adornments. Ancient civilizations often prized gemstones like lapis lazuli, turquoise, and aquamarine for their vibrant colors and purported health benefits, while other gemstones like red garnet were sometimes worn as talismans for protection and good luck. Nowadays, popular gemstones used in engagement rings and other jewelry include diamond, emerald, ruby, and sapphire.
Painite is arguably the rarest gemstone on earth. At the time of its discovery by British gemologist Arthur Charles Davy Pain in 1951, only two specimens of this precious mineral stone existed. However, approximately a thousand more have been unearthed since then.
According to Astteria, an expert in the luxury gem trade, blue diamonds are the most expensive gemstones, valued at $3.93 million per carat. Moreover, flawless samples of these gems are exceptionally rare, making them all the more valuable. A famous example is “The Oppenheimer Blue”, which was sold by Christie’s Geneva for around $57.5 million (which equates to approximately $3 million per carat) in 2016.
The only way to tell if a gemstone is genuine is to take it to a certified jeweler. They will be able to confirm the origin of the stone (i.e., whether it is natural or synthetic) and check for any cracks, scratches, and black spots that are indicators of gem quality.
The diamond is rated the hardest gemstone on the Mohs Scale, with the only substance hard enough to cut a diamond being another diamond.
Gemstones come in a range of colors and a variety of different shapes and sizes. All in all, approximately 200 different gemstones have been identified in the world today. Some of these precious and semi-precious stones are plentiful, while others are rare.
The most expensive gemstone ever sold is the Pink Star Diamond, valued at $83 million.
A birthstone is a gemstone that is symbolic of your birth period, representing either the month or astrological sign. Birthstones make excellent gifts in the form of a ring or a pendant for a necklace.
Gemstones are formed in various parts of the earth’s crust. Most start out as mineral deposits that begin forming crystals when they are exposed to the right amount of heat and pressure. Note that different types of gems require different levels of heat and pressure to start forming crystals. This is due to the chemical composition of the minerals that make up a gemstone.
The International Gem Society lists ten stones that are rarer than a diamond. These are:
Tanzanite
Burma Ruby
Jadeite
Alexandrite
Paraiba Tourmaline
Ammolite
Kashmir Sapphire
Natural Pearl
Red Beryl
Benitoite
Strictly speaking, rubies tend to be rarer than sapphires and are therefore more valuable.
Iron Pyrite (also known as Fool’s Gold) is the ultimate stone of luck, prosperity, and abundance. It is said to attract wealth by summoning the Law of Attraction.
Listed here are the ten most valuable gemstones in the world:
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
A round brilliant cut diamond has the most sparkle compared to other stones, although moissanite comes in close.
A crystal is an object made up of atoms or ions that have been arranged in a specific order and possess a certain structure. Gems, on the other hand, are precious minerals that only occur near their source. Therefore, a crystal can be called a gem, but not vice versa.
April has the most expensive and prestigious of all birthstones: the diamond.
A fine quality ruby is generally more expensive than most emeralds, with record prices of up to $1 million per carat. Emeralds can be purchased for between 525-1125 USD depending on the color and clarity desired – but note that several factors affect the price of a gemstone!
Diamond – The hardest substance on earth, diamonds are considered the most prestigious of all gems. They are also the most popular gemstone used in engagement rings.
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.