Gemstones are pieces of nature’s beauty captured and kept. There’s something about a sparking stone that stops us in our tracks and compels us to claim it. For over 10,000 years, humans have collected and worn gems. Gemstones were once considered little pieces of heaven on earth–either specks of starlight or teardrops of a god–with names inspired by the solar system. They still hold symbolic significance today. Whether you’re looking to add a stunning statement to your gem collection, find your birthstone, invest in an heirloom, or purchase a nugget of wisdom, we’ve created a guide with pictures to help you recognize the stones and their color variations, and understand the meaning and value behind some of the most popular gemstones and their colors.
What is a gemstone?
A gemstone is a precious or semi-precious rock, mineral, or organic material selected for its beauty, cut, and collected or worn. Gemstones are difficult to define since the term is more descriptive than scientific. Not to mention, no two gems are alike. A gemstone must be beautiful, but beauty is subjective and may be determined by trends or the buyer’s preference. Certain qualities, like vibrancy or uniqueness, however, are timeless. Ancient gemstones were treasured as a symbol of status or wealth or used in healing. Today, gemstones are more accessible and limited in their medicinal use, so they’re often selected based on personal significance.
Stones, crystals, and jewels are other names for gemstones but with slight variations.
Crystals vs. gems
Many, but not all, gems are crystals since they’re made up of a crystalline structure of atoms and molecules. A cut and polished crystal is a gem. Gems are fashioned to enhance their beauty and desirability, but crystals are left in their natural form. That doesn’t make them less beautiful, just less like a gemstone and less valuable in the gem market.
Gems vs. jewels
A jewel is an individual gemstone within a piece of jewelry or fashioned to fit in jewelry. There’s not much difference between a gem and a jewel, and the terms can be used interchangeably. However, you would not call a polished but uncut gemstone a jewel.
Stones vs. gemstones
A stone can refer to different solids from the earth in different contexts (i.e., landscaping), but in the context of gemology, “stone” is just a shortened form of “gemstone.”
Is a pearl a gem?
A pearl is an ocean gemstone, like coral. It is considered a gem even though it does not have a crystalline structure. Pearls come from living organisms and are very soft, unlike most gems. “Gem” rather than “stone” may be a more suitable term for a pearl since it does not come from the earth’s surface.
Types of gems
There are over 2,000 natural gemstones, but fewer than 100 of them are worn as jewels, and even fewer are common and easy to purchase. It’s difficult to clarify what characterizes a gemstone, especially to the untrained eye, but gems can be grouped into one of the following three categories.
- Minerals: Most gems are minerals or a combination of minerals, which means they come from the earth’s surface as inorganic material. Gemstones are classified by their mineral species with distinguishable characteristics in composition and structure. A mineral species may include more than one type of gem.
Beryls, for example, are a species that consists of two common gemstones–the emerald and aquamarine. The sapphire and ruby are also in the same species, called corundum. There are many more beryls and corundums than these examples, but they aren’t as well-known.
- Rocks: Rocks are inorganic gems, but they are not “precious.” Many rocks, like the lapis lazuli, were once highly valued for healing, but their abundance makes them less valuable in the current market where rarity is significant.
- Organic gems: These come from living organisms–tree sap that produces amber or a mollusk that makes a pearl. Organic gems are easy to distinguish by their softness, which makes them less durable than inorganic gems.
Precious stones vs semi-precious stones
There are only four precious stones: diamond, sapphire, emerald, and ruby. These gems are precious by popular demand and tradition, not because they are any rarer or more special than semi-precious stones. Buying a precious stone is important if you’re interested in an investment piece. The four precious stones are the hardest and have the most longevity. They are the tried-and-true gemstones with universal appeal.
Many people shop specifically for precious or semi-precious jewels, but these descriptions are determined by demand, not science, and do not need to be a priority in your gemstone selection. Instead, choose something you find meaningful or beautiful. A semi-precious gemstone may be rarer and of a higher quality than a precious stone you’re considering. Precious stones are more popular and, therefore, more expensive, so if color matters most to you, there are less expensive but just as beautiful options. Think about what is most precious to you.
Value of gemstones
The value of gemstones fluctuates based on market trends, and there are no set criteria that determine a gem’s value. Diamonds are the exception and do have world-recognized standards. A stone’s price is measured in carats, but the price per carat is important for gem traders, not jewelry shoppers. A two-carat stone is not twice as expensive as a one-carat stone; it could be three to four times the cost because of the rarity of the size. Gemstones must also be cut, polished, and set. All processes must be accounted for in the final cost of jewelry.
Gems are graded and valued by the four C’s: carat, color, clarity, and cut, but these factors vary depending on the type or species of the gemstone. Here are several features that may or may not be important in determining the value of a particular gem.
- Color is the most important aspect of a gem’s quality. The brighter the better. But when a colorless or white stone is preferred, any trace of color could lower the value.
- Features can make or break a gem’s desirability. Certain features are flaws, while others add character. Deep fractures in a stone make it more susceptible to breaking, and dark markings usually decrease color and clarity. Asterism (star) and mineral inclusions, on the other hand, are desirable.
- Durability makes some gems more desirable for jewelry than others. This is one reason precious stones have historically remained popular.
- Rarity often trumps durability. Pearls and opals are very soft and often cheaper than precious stones, but the rare types may be more valuable than a diamond or ruby.
- Clarity is important for some gems but not as important for others. All emeralds have visible inclusions but peridots are clearer, so clarity affects their quality more than an emerald’s.
- Size may be important if a large type of stone is both rare and appealing. Large amethysts are more common than large rubies, so size doesn’t contribute as much value to an amethyst as it does a ruby.
- Cut quality is not determined by the stone but by the artistry of the lapidary. The desirability of a certain cut is largely determined by fashion and preference.
Gemstone properties are the characteristics that give a gem personality, and there are many. Gemologists use these characteristics to identify and distinguish between similar types of gemstones. Below are some of the main properties you may encounter as you research gems.
- Hardness is measured from 1 (soft) to 10 (hard) on the Mohs Hardness Scale. Stones with scores lower than 7 are usually not ideal gems for jewelry. A higher score means a gem is suitable for long-term wear. A 1-3 hardness gemstone can be scratched with a fingernail or penny.
- Density is important when measuring the size of stones. A gemstone may have a shorter diameter but a heavier weight in carats (and higher value) than another larger stone because of its density.
- Color: The color of a gem comes from the minerals it contains. A cut can manipulate the color when it changes the distance the light passes through the gem.
- Response to light: This includes a stone’s refraction and absorption of light, as well as its transparency and luster.
- Special effects: Some unique properties include asterism (a star created where light rays cross through a stone’s thin inclusions), chatoyancy (cat-eye), iridescence (rainbow), opalescence (opaque and glossy look), and inclusions.
A gem’s mineral make-up determines its primary and secondary colors. The same gemstone from one location may have a distinctly different hue or tone because of the minerals in the soil. Myanmar, Sri Lanka, and Thailand mine rubies but each in different shades of red. Gemstone color can be enhanced with heat treatment to make it more vibrant or to change the color completely, which is how the blue topaz is created. Some gems, like spinel, come in many colors and are a great alternative to precious stones. Pleochroism refers to different hues displayed at different angles of a gemstone.
List of popular gemstones by color
The number of gemstones reaches the thousands, but even with gemstones galore, only a handful are popular. Color quality defines the gemstones that make it to the top of the popularity list. So we’ve narrowed our type of gemstones list to 12 of the most common stones, arranged it by color, and included meanings and pictures for reference.
Blue gemstone: Sapphire
The bluer the better when it comes to a sapphire’s value. Of course, that’s excluding all other sapphire colors. You can find sapphires in nearly every color, but the stone is most renowned for its striking blue hue. Star sapphires that exhibit asterism are among the rarest of this type of gem. Kashmir sapphires are extremely rare since they have been emptied from the mines in the Himalayas for nearly a century. Very fine inclusions give the Kashmir sapphire a silky smooth cornflower blue.
Gem meaning: wisdom and loyalty
Pleochroism: Yes (blue and purple)
Calendar significance: September birthstone, Sagittarius sign, Wednesday stone
Blue-green stone: Blue Topaz
The blue topaz is a naturally yellow topaz that’s undergone heat treatment to give it its bright blue color. Blue topaz comes in different tones–Swiss blue as the lightest and London blue as the darkest. But the blue-green topaz falls in between the two. Any shade of blue topaz could be an alternative to more pricey blue gemstones.
Gem meaning: Tranquility and communication
Pleochroism: Weak (blues)
Calendar significance: December birthstone
Light blue gemstone: Aquamarine
If seafoam could crystallize, it would look like an aquamarine. The stone is a type of beryl like the emerald, but it’s clearer with fewer inclusions. An aquamarine’s clarity can increase its value.
Gem meaning: Peace and relaxation
Pleochroism: Yes (light blue and light green)
Calendar significance: March birthstone (modern)
Red gemstone: Ruby
The ruby only comes in red, but every shade is unique. Rubies are a type of corundum like sapphires and can also exhibit asterism. The deeper the red, the more valuable the Ruby. The rarest rubies are pigeon’s blood color–deep red with a hint of blue.
Gem meaning: Love, passion, power
Pleochroism: Yes (yellow-red and deep red)
Calendar significance: July birthstone, Tuesday stone
Green gemstone: Emerald
You won’t find a “flawless” emerald. Its inclusions add character and convey a story of how the stone was formed. But inclusions should be thin and linear, not bubbled or deep fractures. The deeper and richer the green, the more desirable the emerald.
Gem meaning: Vitality, energy
Pleochroism: Yes (blue-green and yellow-green)
Calendar significance: May birthstone, Friday stone
Light green gemstone: Peridot
The peridot was an ancient Egyptian favorite for warding off evil. The most valuable peridots are more lime than olive. Peridots are clear and highly refractive, so watch out for little black dots that often taint this gemstone.
Gem meaning: Creativity
Pleochroism: Weak (greens)
Calendar significance: August birthstone (modern)
Yellow gemstone: Citrine
The citrine is sometimes yellow and sometimes orange, which is why it’s a stone for both Virgo and Libra. Hues resembling honey and sunshine give the wearer a radiant glow. Orange or yellow, brightness is key, so avoid purchasing brownish citrines.
Gem meaning: confidence and kindness
Pleochroism: Weak (yellow)
Calendar significance: November birthstone (modern), Virgo (yellow) & Libra (orange)
Purple gemstone: Amethyst
The amethyst is one of the most mystical and meaningful gemstones with symbolic value in ancient religion, royalty, and medicine. The stone is believed to lend emotional control and help the wearer overcome temptation. Dark, royal purple amethysts are most valuable.
Gem meaning: Temperance and love
Pleochroism: Weak (reddish or greyish violet)
Calendar significance: February birthstone, Pisces, Thursday stone
White gemstone: Pearl
The raw, uncultured pearl is the rarest of its kind. These often have an off-white tint and a more irregular shape. Most pearls are cultured and naturally occurring ones are increasingly difficult to find. The moonstone is another milky-white stone that holds a similar meaning as the pearl.
Gem meaning: Truth and purity
Calendar significance: June birthstone (modern), Monday stone
Black gemstone: Onyx
The elegant black onyx is a form of chalcedony or a layered stone used for engraving. These gems hold unique value in their setting or design. Black onyx is often engraved, used to create cameo jewelry, or placed in an intricate setting.
Gem meaning: Stamina and self-confidence
Calendar significance: Capricorn
Bi-color gemstone: Watermelon Tourmaline
Just like its namesake, the watermelon tourmaline has a layer of green, white, and then pink. The tourmaline comes in many colors, the rarest being the electric blue Paraiba tourmaline. But the watermelon stone is certainly one of the most interesting types of tourmaline.
Gem meaning: Kindness and compassion
Pleochroism: Yes (red)
Calendar significance: October birthstone (modern)
Multi-color gemstone: Opal
The opal exhibits no pleochroism but plenty of colors. The stone is formed from the remnants of raindrops. The harlequin opal is the most colorful and rare with the black opal coming in second. Generally, the darker the opal, the more valuable it is.
Gem meaning: Magic, misfortune, playfulness
Calendar significance: October birthstone (traditional)
Gemstones are believed to hold symbolic meaning and healing power. Although gems have not been proven to cure illness, they may promote mindfulness for some, which can lead to emotional and physical healing. Even if you don’t use stones for healing, knowing their symbolic meaning can be a fun way to personalize a gemstone.
- Ruby for passion
- Moonstone for fertility
- Sapphire for loyalty
- Diamond for lasting love
- Any other gemstone that holds special meaning for your relationship
Learn how to find the perfect gemstone engagement ring to symbolize your love.
Once perceived “evil” or negative gemstones
- Opal–this stunning gem that was thought to bring happiness to ancient people gained a negative perception in the nineteenth century. According to legend, only October babies are protected from the opal’s negative energy. Today, these beautiful gems are no longer believed to have negative energy and are one of the most popular gemstones.
- Pearl–the pearl became a symbol of misfortune likely because of its delicacy. Its tendency to break was interpreted as a bad omen. This is not the case today–pearls are remembered and adored for their symbols of purity and elegance.
Gemstones for anxiety
- Citrine for joy
- Amethyst for emotional control
- Turquoise for emotional balance
- Aquamarine for calm
Gemstones for protection
- Amethyst for spiritual protection
- Garnet for boldness in adversity
- Peridot for protection from evil
Gemstones for strength
- Moonstone for inner strength
- Garnet for triumph and success