Gemstone Types

In this guide we explain the symbolic, historical and practical differences among an array of beautiful gemstones so you can make an empowered choice to fit your taste perfectly.


Available in all the colors of the rainbow, there are different types of gemstones to suit every taste and budget. Here is a brief introduction to the gemstones featured on the ICONIC site. This list of gemstones features additional detailed information about its history, photos, and other relevant facts.

Gemstone hardness refers to the Mohs’ scale of mineral hardness, which runs from 1 (softest) to 10 (hardest).

Precious Stones

precious stones


Hardness: 10 (extremely hard)

Though often treated as a separate category, diamonds are in fact a gemstone. Uniquely strong and brilliant, diamonds have become a symbol of eternal love and the most popular gemstone for engagement rings. The name “diamond” stems from the ancient Greek word “admas”, used to describe something unbreakable or invincible.

Most diamonds on the market are white diamonds, prized for their colorlessness. Fancy-color diamonds are extremely rare and valuable. For a unique colored diamond, you may want to consider a black diamond. To learn more about diamonds, visit Diamond Education.

Birthstone: April

Anniversary: 10th, 60th

Choose Gem Emerald1


Hardness: 7.5-8 (medium-very hard)

The gemstone of spring, emeralds symbolize rebirth. Cleopatra, the ancient Egyptian ruler and beauty, was known for her love of emeralds.

A type of beryl, the same mineral species as aquamarine, emerald color ranges from green to bluish green. Color is the single most important factor in evaluating emeralds and the more intense the color, the greater the value.

Rarely eye-clean, emeralds are one of the few gemstones where visible inclusions (referred to as the “jardin”) are acceptable.

Birthstone: May

Anniversaries: 20th, 35th

Choose Gem Ruby1


Hardness: 9 (very hard)

Referred to as the “king of gems”, rubies have for centuries been the gemstone. A variety of the corundum mineral species, rubies can sell for the highest price per carat of all colored gems.

Rubies are found in hues of red ranging from orange-red to purplish-red. Ruby is often heat treated to intensify color and improve clarity.

With a name stemming from the Latin word for red (“ruber”), fiery ruby is symbolic of love and passion.

Birthstone: July

Anniversary: 15th, 40th

Choose Gem Sapphire1


Hardness: 9 (very hard)

With a name that comes from the Greek word for blue (“sappheiros”), it is easy to understand why many people are surprised to learn that sapphire is available in a variety of colors. Popular sapphire colors include pink, yellow, and white.

Known as the gem of truth and fidelity, blue sapphire is a particularly popular choice for engagement rings. Princess Diana was one of the most famous wearers of a sapphire engagement ring- the very same ring now worn by Duchess of Cambridge.

As with rubies, sapphires are often heated to enhance their color and clarity.

Birthstone: September

Anniversary: 5th, 45th

Choose Gem Black Diamond1

Black Diamond

Hardness: 10 (extremely hard)

Gem variety: Bold and mysterious, black diamonds make a statement, especially when paired with white diamond.

In nature, black diamonds get their color from the presence of dark inclusions. Today, most black diamonds are diamonds that have been heat-treated, which then turns dark green to the point of appearing black.

Birthstone: January

Anniversary: 2nd

Choose Gem Amethyst1


Hardness: 7 (medium hardness)

Found in hues of purple, amethyst is the most valuable variety of the mineral quartz. Throughout history, amethyst 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 worth as much as ruby. Today, amethyst is a more affordable but still very popular gemstone.

Birthstone: February

Anniversary: 6th, 17th

Choose Gem Citrine1


Hardness: 7 (medium hardness)

Citrine is a warm, earth toned variety of quartz. The color of citrine ranges from pale yellow to orange brown. Often confused with topaz, the two gemstones share the status of November birthstone.

Natural citrine is very rare. Most citrine is the product of heating amethyst, another variety of quartz.

Referred to as the “merchant’s stone” or “money stone”, citrine is believed by some to bring prosperity.

Birthstone: November

Anniversary: 13th

Choose Gem Blue Topaz1


Hardness: 8 (very hard)

This gem exists in shades of brown, yellow, green, blue, red, pink, orange, and purple, as well as colorless.

Blue, the most popular color and is actually the rarest in nature. Most blue topaz is the result of irradiation and heating. These treatments turn colorless or pale stones into beautiful shades of blue, such as Swiss and London blue.

Birthstone: November (precious topaz), December (blue topaz)

Anniversary: 4th (blue topaz), 23rd (imperial topaz)

Choose Gem Garnet1


Hardness: 6.5-7.5 (medium hardness)

There are many varieties and colors of garnet, the most well-known of which is red garnet. Intense and fiery red garnet has been popular for millennia. Archeologists have discovered ancient garnet jewelry dating back over 5,000 years. Garnet was believed to protect travelers; in the story of Noah’s Ark, Noah uses a garnet lantern to light the way.

Non-red varieties of garnet include green Russian demantoid and African tsavorite, pink and purple rhododendron, and orange to brown spessartite and hessonite.

Birthstone: January

Anniversary: 2nd

Choose Gem Black Onyx1


Hardness: 7 (medium hardness)

Onyx is a banded variety of the mineral chalcedony. An ideal texture for carving, onyx was often used in ancient Rome and Greece to produce cameos and wax seals.

Most onyx used for jewelry today is black, white, or red, in which case it is called ‘sardonyx’. Most black-colored onyx is the result of chemical treatment, a practice that has been common for thousands of years. One technique, described by the Roman philosopher Pliny the Elder in the first century, included soaking chalcedony in sugar water. The glossy noir of black onyx is perfect for art deco designs or as a contrast to a white diamond.

Anniversary: 7th

Choose Gem Peridot1


Hardness: 6.5-7 (medium hardness)

Called the “gem of the Sun” by the ancient Egyptians, peridot is one of the few gemstones found in only one color: green. Vivid lime green is the most desirable color for peridot, though hues can range from light green to olive green.

Formed in the heat and pressure of the earth’s mantle, peridot also exists in outer space. Peridot crystals have also been found in pallasite meteorites (asteroid or comet debris that has fallen to earth).

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 naturally occurring mineral crystal which will have formed over millions of years. When cut and polished, they are frequently used in jewelry. Some organic materials which are used in jewelry can sometimes be referred to as “gemstones”, although strictly speaking, this is incorrect.
The rarest gemstone is Painite which was first discovered in 1951, and recognised as a mineral in 1957, by a British gemologist called Arthur Charles Davy Pain. For many years there was only one example of this dark red crystal, and it was on display in the British Museum in London.
The most expensive gemstone is the Blue Diamond at $3.93 million per carat. It has all the properties of a diamond but has a blue colour due to the trace element boron. They can be graded from FL to I3.
Real gemstones are becoming increasingly difficult to identify due to the increased quality of synthetic stones. An expert will check the smoothness of the surface with natural stones having a slightly rough texture. They will also check the malleability (hardness) of the stone and their hue against detailed, official descriptions of different minerals.
The diamond would be regarded as the hardest gemstone in the world, but that doesn’t equate to being the most robust. They are known to be almost resistant to scratches and abrasions, but they can be fractured of cleaved by a hard blow. There is a common misconception that diamonds should be struck with a hammer to test their authenticity. However, this is not an advisable or reliable means of checking.
There are approximately more than 200 different types of stones available.
Rare gemstones like the red diamond can fetch over $1 million per carat and there are less than 30 red diamonds found in the world.
birthstone is a gemstone that represents a person’s period of birth that is usually the month or zodiac sign. 
Many minerals form beautiful crystals, but the most prized of all are gemstones. For example, diamonds are made up of carbon atoms which are the hardest natural substance found on Earth. Rubies are formed of a mineral called corundum, comprised of aluminium oxide and emeralds are formed of a mineral called beryl whose chemical formula is a complex mix of beryllium, aluminium, silicon, and oxygen.
The list of precious stones rarer than diamonds are:
The Intense violet-blue hues of tanzanite, the bright electric green of imperial jade- jadeite, alexandrite from Russia’s Ural Mountains, brightly saturated blue-green hues of paraíba tourmaline, iridescent ammonites, soft velvety, saturated blues of Kashmir sapphires, natural pearl, the red variety of beryl,  and dark to saturated sapphire blue of the benitoite gem.
Although rubies and sapphires are composed of the same mineral known as corundum, rubies are significantly rarer than sapphires and therefore much more expensive.
Citrine is the stone of prosperity, wealth, protection and good luck.
A brief list of gemstones that are considered most valuable:
Black Opal 
Red Beryl
the way gems are cut influences the brilliance and sparkle of the stones. A round cut diamond has lots of sparkle. Sapphires are known to be the shiniest and one of the hardest precious stones. Spinel is also considered to be one of the precious stones with exceptional sparkle.
A crystal is not a gemstone. The gem is a rare mineral that is highly-priced and considered to be precious stones. Common crystals are rose quartz, amethyst, and turquoise.
The April birthstone of a diamond is the most expensive stone.
Rubies usually generate a higher price than emeralds.