Gemstone Guide

In the past, it was common for wedding jewelry to contain stones other than diamonds. This is why you'll find many antique engagement rings adorned with sapphires, rubies, emeralds, or even aquamarine and pearls.

While the diamond has been the most popular wedding jewelry stone for quite a while now, the tide is turning, and other gemstones are once again becoming popular.

Whether you're buying an engagement ring, a necklace, a brooch, or any other piece of jewelry, you may be curious about the gemstones it features. That's why we created this guide for you to learn more about just a handful of the beautiful gemstones that adorn all types of fine jewelry.

The Mohs Scale of Mineral Hardness

You probably already know that the diamond is one of the hardest substances in the world. Yes, it really can cut glass. However, other gemstones can scratch glass, because they're nearly as hard as diamonds.

The hardness of a mineral (and all gemstones are minerals) is measured by the Mohs Mineral Hardness Scale, which was created in 1812 by German geologist and mineralogist Friedrich Mohs. The scale rates minerals from 1 (softest) to 10 (hardest).

For example, talc, which is used to make talcum powder, is a 1 on the Mohs Scale. It can easily be scratched just with a fingernail. A diamond is a 10 on the scale, and can only be scratched by another diamond.

Some minerals have a range of hardness, usually depending on where the gem was mined. This is because mines in different parts of the world may produce the same gemstones, but with slight differences due to the concentrations of minerals and impurities in the deposits.

The harder a mineral (gemstone), the more durable it is. This is partly why, aside from their beauty, some harder gemstones such as diamonds (10), rubies (9), and aquamarine (8) are popular choices for jewelry. Some softer stones are also used in jewelry, such as amber (2.5) or pearls (2.5 - 4.5), but this makes for very delicate pieces that must be worn and stored with great care.


The most coveted gemstones add sparkle, shine, color, and durability to the jewelry they grace.


Birthstone Month: April
Origins: Angola, Australia, Botswana, Canada, India, Russia, South Africa, United States
Mohs Scale Hardness: 10
Symbolism: Innocence, Love
Available Colors: White/Clear

Part of the reason diamonds are so brilliant is their atomic makeup. Light normally travels at 186,000 miles per second. The qualifier for this, though, is that light must be traveling through a vacuum to achieve that speed.

Diamonds are so densely packed with electrons, light slows to less than half that speed, traveling through diamonds at just 80,000 miles per second

Colored Diamond

Origins: Australia, Brazil, Guyana, India, Indonesia, South Africa, Venezuela
Mohs Scale Hardness: 10
Available Colors: Black, Blue, Brown, Champagne, Gray, Green, Orange, Pink, Purple, Red, Yellow

Truly colorless diamonds are formed from pure carbon. Slight imperfections and impurities in white diamonds can cause yellowing or cloudiness, which detracts both from the stones' beauty and price.

However, when imperfections and impurities occur at higher degrees, diamonds (and other gemstones, in fact) of brilliant colors can be created. For example, a small amount of boron trapped in the crystal structure will create a blue diamond. This is a rare occurrence. Roughly one out of every 200,000 diamonds found in the world is blue, and the resulting color is usually very light. This is why the deep blue Hope Diamond is so valuable. It's truly one of the rarest stones in the world.


Birthstone Month: May
Origins: Afghanistan, Australia, Brazil, Colombia, Egypt, Pakistan, Russia, United States, Zambia
Mohs Scale Hardness: 7.5 - 8
Symbolism: Happiness, Fertility
Available Colors: Green

Emeralds are a variety of the mineral beryl, and get their green color from trace amounts of chromium or vanadium occurring in the crystal structure.

While diamonds are considered more beautiful and valuable the fewer inclusions they have, for emeralds, it's all about the color. Truly transparent emeralds without any inclusions are extremely rare, so inclusions are more accepted for this stone.

Emerald inclusions often have the appearance of a garden, so they're referred to as jardin, which is French for garden. Jacqueline Kennedy received a stunning emerald and diamond engagement ring from JFK.


Birthstone Month: July
Origins: Afghanistan, Australia, Brazil, Burma, Cambodia, Colombia, India, Japan, Myanmar, Namibia, Pakistan, Scotland, Sri Lanka, Thailand
Mohs Scale Hardness: 9
Symbolism: Nobility, Beauty
Available Colors: Red

Again, it's extremely rare to find rubies without any inclusions at all, so the quality of the stones hinges heavily on their color. Stones vary from deep red, even with purplish tones, to light pink. In many cases, pink rubies are instead labeled as pink sapphires.

Don't worry-no one's pulling a fast one. Rubies and sapphires are actually varieties of the same mineral, corundum. Rubies get their red color from the presence of chromium, while sapphires are blue due to titanium and iron.

The most common ruby inclusions are thin mineral filaments called needles. When these needles intersect, creating a criss-cross pattern, the inclusions are called silk. When a ruby is cut with a curved upper surface, the silk creates a vibrant star effect, called asterism. These stones are referred to as star rubies.


Birthstone Month: September
Origins: Afghanistan, Australia, Brazil, Cambodia, China, Colombia, India, Kashmir, Kenya, Laos, Madagascar, Malawi, Nepal, Nigeria, Pakistan, Sri Lanka, Tajikistan, Tanzania, Thailand, United States, Vietnam
Mohs Scale Hardness: 9
Symbolism: Wisdom, Calm
Available Colors: Black, Blue, Green, Orange, Pink, Purple, White, Yellow

The most common color for sapphires is a deep blue but sapphires of colors other than blue can be just as bright and beautiful as the traditional blue stones.

Pink sapphires are actually very lightly colored rubies. (See the Ruby section) However, many gemologists and jewelers maintain that the pink stones are rubies because it's very difficult to definitively determine where red ends and pink begins.


Birthstone Month: June
Origins: Brazil, India, Madagascar, Myanmar, Russia, Sri Lanka, Zimbabwe
Mohs Scale Hardness: 8.5
Symbolism: Balance, Joy
Available Colors: Green in sunlight; Purplish Red in incandescent light

Alexandrite was named after Russian czar Alexander, as it was first discovered in Russia's Ural mountains in 1830, the year Alexander came of age.

In addition to being June's birthstone (along with the pearl), it's also the gem for the 55th wedding anniversary.

The most notable feature of Alexandrite is its ability to change color depending on the ambient light. In sunlight, higher-quality stones are bluish-green, while lower-quality have a more yellow tinge. In incandescent light, higher-quality stones turn a deep, purplish-red, while lower-quality stones become brownish.

Once found in abundance, Alexandrite is now in low supply, which may have an effect on its desirability and price.


Birthstone Month: February
Origins: Brazil, Germany, Madagascar, Russia, Uruguay
Mohs Scale Hardness: 7
Symbolism: Sincerity, Peace
Available Colors: Purple

Amethyst was first discovered in 3000 B.C.E. It was believed to have mystical and medicinal properties. Leonardo da Vinci wrote that amethyst increases intelligence, and rids the mind of evil thoughts.

The ancient Greeks believed the stone could cure or prevent intoxication. In fact, the Greek word amethystos means "not drunken." This word was eventually shortened to become the gemstone's name.

Amethyst is actually a type of quartz, and gets its royal purple color from aluminum and iron impurities. In the early 19th century, large deposits were discovered in Brazil.


Birthstone Month: March
Origins: Angola, Brazil, Kenya, Madagascar, Malawi, Mozambique, Nigeria, Pakistan, Russia, Tanzania, United States, Zambia
Mohs Scale Hardness: 7.5 - 8
Symbolism: Courage, Health
Available Colors: Light to Deep Blue

Its name comes from the Latin aqua marinus, meaning "water of the sea," and its color ranges from a light, sky blue, to a deep ocean blue.

Like the emerald, the aquamarine is a variety of the mineral beryl, and gets its blue color from the presence of iron in the crystal structure. In addition to being the March birthstone, it's also the gem for the 19th wedding anniversary.

Aquamarine engagement rings were popular in the 1920s, and are once again a highly desirable choice for those looking for something other than diamonds.


Birthstone Month: November
Origins: Bolivia, Brazil, France, Madagascar, Russia
Mohs Scale Hardness: 7
Symbolism: Abundance, Generosity
Available Colors: Orange, Yellow

Like amethyst, citrine is a type of quartz. In fact, citrine is amethyst quartz that has been heated, which changes the color from purple to a deep orange-brown or reddish-brown. This sometimes occurs naturally, but more often is manmade.

Natural citrine does occur, and is a much lighter yellow color. It's from this natural mineral that the stone gets its name. Citrine is a derivative of citron, which is "lemon" in French. Natural citrine is also sometimes called "lemon quartz."

Most citrine comes from Brazil, but is mostly heat-treated amethyst. Natural citrine is quite rare, and usually found in France, Madagascar and Russia.

In addition to being a November birthstone, citrine is also the gemstone for the 13th wedding anniversary.


Birthstone Month: January
Origins: Kenya, Madagascar, Russia, Tanzania, Turkey, United States
Mohs Scale Hardness: 6.5 - 7.5
Symbolism: Constancy, Loyalty
Available Colors: Blue, Green, Orange, Red

Garnet is mined in at least 14 states in the U.S., some locations producing gemstone-quality minerals, while others produce industrial-grade garnet.

Industrial garnet has many uses. Garnet sand is used in water filtration systems, and is commonly used instead of silica for sand blasting and cutting steel. Garnet sandpaper is highly prized by carpenters for finishing wood.

Its name comes from the Latin granatus, meaning "like a grain."

In addition to being the January birthstone, garnet is also the gemstone for the second wedding anniversary.


Birthstone Month: October
Origin: Australia, Brazil, Honduras, Mexico, United States
Mohs Scale Hardness: 5.5 - 6.5
Symbolism: Good Luck, Hope
Available Colors: White, blue or black with multicolored flecks

Although opals are found around the world, Australia produces roughly 95% of the opals found in today's market.

Opals are now considered to be gemstones of good luck, but there was a time when they were thought to be the opposite. It seems this stems from Anne of Geierstein, a novel written by Sir Walter Scott, and published in 1829. In the story, a woman wears an opal in her hair. When it comes into contact with water, the stone loses its color and luster. The following day, the woman is revealed to have been a demon.

Readers took this as a warning of the opal's bad luck properties, and stopped buying jewelry with the stone, causing a tremendous downturn in the opal market for 50 years.

It wasn't until Queen Victoria began wearing opals, and giving them as wedding gifts to her daughters, that the gemstone came back into favor, and regained its status as a good luck stone.

The opal's name may come from the Greek opallos, which means "to see a change (of color)," or from the Sanskrit upala, meaning "valuable stone."


Birthstone Month: June
Origins: Australia, China, French Polynesia, Japan, Philippines
Mohs Scale Hardness: 2.5 - 4.5
Symbolism: Purity, Innocence
Available Colors: Black, Blue, Brown, Cream, Gold, Gray, Green, Pink, Purple, Silver, White

Perfectly round pearls are the rarest to find, and most difficult to culture. For this reason, they're usually higher in price than other shapes. That said, pear, oval and baroque (slightly irregular) pearls are also popular, and can be just as beautiful as round.

The easiest way to tell the difference between real pearls and fake is to rub them against your teeth. Fake pearls will feel smooth, while real pearls will have a slightly rough texture. Fake is not to be confused with cultured, though. Cultured pearls are real pearls that have simply been carefully farmed. Fake pearls are usually glass beads covered in lacquer.


Birthstone Month: August
Origins: Australia, Brazil, China, Egypt, Kenya, Mexico, Myanmar, Norway, Pakistan, Saudi Arabia, South Africa, Sri Lanka, Tanzania
Mohs Scale Hardness: 6.5 - 7
Symbolism: Felicity, Protection
Available Colors: Yellow-Green

Peridot is an ancient gemstone. It's found in a pallasite meteorites, remnants of the formation of our solar system. In 2005, it was also discovered in comet dust brought to Earth by a space probe.

While most gemstones come in multiple colors, peridot is only available as a yellow-green stone. It derives its color from the presence of iron.

In addition to being the August birthstone, it's also the gemstone for the 15th wedding anniversary.


Birthstone Month: December
Origin: Tanzania
Mohs Scale Hardness: 6 - 7
Symbolism: Power, Healing
Available Colors: Blue, Violet, Bluish-Purple

While most gemstones are found in countries around the world, tanzanite is only found in one place-Tanzania, where it was discovered in 1967, and for which it is named. This makes it even rarer than the diamond.

The name originally proposed for the stone was "blue zoisite." Thinking that an inappropriate name, the gemstone's main distributor, Tiffany & Co., proposed "tanzanite" in honor of its origin.


Birthstone Month: November
Origins: Brazil, Madagascar, Mexico, Myanmar, Namibia, Nigeria, Pakistan, Sri Lanka, United States
Mohs Scale Hardness: 8
Symbolism: Friendship, Strength
Available Colors: Blue, Brown, Clear, Green, Orange, Pink, Red, Yellow

While blue topaz does occur naturally, it's possible to turn a clear topaz into a blue stone with radiation and/or heat treatment.

According to Greek mythology, topaz could increase strength, and render its wearer invisible.

In addition to being the November birthstone, topaz is also the gemstone for the 4th wedding anniversary.


Birthstone Month: October
Origins: Afghanistan, Brazil, Kenya, Madagascar, Mozambique, Namibia, Nigeria, Pakistan, Russia, Tanzania, United States, Zambia
Mohs Scale Hardness: 7 - 7.5
Symbolism: Balance, Endurance
Available Colors: Blue, Green, Red, Yellow

Most blue and green tourmaline stones get their colors from traces of iron and titanium. However, certain gemstones from Brazil are vivid greens and blues because of copper impurities.

One variety of the stone is called watermelon tourmaline because-you guessed it-it's green on the outside, and a beautiful pink or red on the inside, sometimes with a slight band of clear or white stone in between.

When tourmaline stones are heated and allowed to cool, they become electrically charged. If this process is done repeatedly, a tourmaline stone can actually generate usable electric power. As of yet, this has not been done on a commercial scale.


Birthstone Month: December
Origins: China, Egypt, Iran, Mexico, United States
Mohs Scale Hardness: 5 - 6
Symbolism: Courage, Friendship
Available Colors: Bright Blue, Green

Turquoise requires dry, environments to form. For this reason, it's only found in a few deserts around the world. When acidic, copper-rich groundwater seeps into the ground, and then reacts with minerals that contain aluminum and phosphorus, turquoise is the result.

Blue turquoise gets its color from copper, while green is produced by iron impurities.

Turquoise jewelry has been discovered buried in ancient Egyptian tombs dating back to 4000 B.C.E., making it some of the oldest jewelry in the world. The ancient Egyptian word for turquoise was mefkat, which means "delight" and "joy."

While smooth, even-colored turquoise is the most sought after, some turquoise stones contain remnants of the rock that surrounded it, which are called matrix. Some matrix forms web-like patterns, and the stones that feature them are called spiderweb turquoise.


Birthstone Month: December
Origins: Australia, Cambodia, China, Madagascar, Myanmar, Sri Lanka, Tanzania
Mohs Scale Hardness: 6.5 - 7.5
Symbolism: Wisdom, Wealth
Available Colors: Blue, Brown, Clear, Green, Red, Yellow

Despite its name, zircon is not at all related to cubic zirconia. In fact, it's more like diamond due to its brilliance and fire.

It's is found in several countries around the world, but zircon found in Australia is the oldest mineral in the world at 4.4 billion years of age. In fact, zircon contains radioactive trace elements that actually measure the passage of time, so the mineral is like a geological clock.

Shop our diverse collection of antique engagement rings, which feature gorgeous gemstones of all kinds.

Top of page