Peridot: Gemstone, Color, Properties and Value

Peridot is a vibrant yellowish-green gemstone and a gem-quality variety of the mineral olivine. Its unique color, ranging from golden lime to deep olive green, comes from iron in its crystal structure—the more iron, the darker the shade. The finest peridot has a pure, bright green hue with no brown or yellow undertones.

Prized since ancient times, peridot has been associated with beauty, protection, and even magical powers. It is the birthstone for August and is sometimes called the “evening emerald” because its rich green glow remains vivid under artificial light.

Beyond Earth, peridot has been discovered in certain meteorites, suggesting it may also form on other planets and asteroids. This cosmic connection, along with its striking color, makes peridot one of the most distinctive gemstones in the world.

Natural peridot gemstones showcasing signature green colors – from yellowish-olive to intense lime, all magnesium silicate (olivine) birthstones for August.

Formation of Peridot

Peridot is formed in the upper mantle of the Earth, where it is found in association with other mafic and ultramafic rocks. These rocks are rich in iron and magnesium, which are the two elements that give peridot its characteristic green color. Peridot is brought to the surface by volcanic activity, where it can be found in lava flows and other igneous rocks.

Properties of Peridot

Composition: Peridot is a magnesium iron silicate, specifically a variety of the mineral olivine. Its chemical formula is MgFeSiO₄, where magnesium and iron can be present in varying proportions.

Peridot Physical Properties

Color: Peridot is known for its beautiful green color, ranging from light yellowish-green to deep olive green. The color is caused by the presence of iron in the crystal structure.
Luster: Peridot has a vitreous luster, meaning it has a glassy shine.
Streak: Peridot has a white streak, meaning that when scratched on an unglazed porcelain plate, it leaves a white powder.
Hardness: Peridot has a hardness of 6.5-7 on the Mohs scale of mineral hardness. This means it can scratch glass but not steel.
Cleavage: Peridot has imperfect cleavage in two directions. This means it can break along specific planes with moderate ease.
Crystal Form: Peridot crystals can be found in various forms, including prismatic, tabular, and granular.
Density: Peridot has a density of 3.30-3.40 g/cm³, making it a relatively heavy mineral.
Transparency: Peridot can be transparent, translucent, or opaque, depending on the presence of inclusions and other factors.
Fracture: Peridot has a conchoidal fracture, meaning it breaks with smooth, curved surfaces.
Specific Gravity: The specific gravity of peridot is slightly higher than its density, ranging from 3.33 to 3.47.
Solubility: Peridot is insoluble in water and most acids but can be dissolved by strong hydrofluoric acid.
Magnetism: Peridot is weakly magnetic due to the presence of iron in its structure.

Peridot Optical Properties

Fluorescence: Peridot can exhibit weak fluorescence, appearing slightly yellowish-green under ultraviolet light.
Pleochroism: Peridot exhibits slight pleochroism, meaning its color can appear slightly different depending on the viewing direction.
Refractive Index: Peridot has a refractive index that ranges from 1.654 to 1.690. This value indicates how much light bends as it passes through the peridot, contributing to its brilliance.

Peridot Additional Properties

Inclusions: Peridot can contain various inclusions, such as chromite, spinel, and nickel-iron alloys. These inclusions can affect the color, transparency, and value of the gem.

Shield-cut peridot gemstone from Tanzania.
Photo © Joel E. Arem

Peridot Colors

The primary cause of peridot's green color is the presence of iron within its crystal structure. Specifically, iron substitutes for magnesium in the mineral's formula (MgFeSiO₄). The amount and type of iron present significantly influence the perceived color:

Iron Content:

Higher iron content (10-20%) Leads to deeper, darker green shades of peridot, ranging from olive green to near blackish-green. This is because iron absorbs specific wavelengths of light, leaving the remaining green wavelengths to be reflected and perceived by the eye.

Lower iron content (5-10%) Results in lighter, yellowish-green to lime green shades. Minerals with very low iron content are called forsterite and are colorless.

Occurrence of Peridot

Peridot is found in igneous rocks, such as basalt and peridotite. It is also found in some meteorites. The largest peridot deposits are found in the deserts of Egypt and Pakistan. Smaller deposits are found in the United States, Brazil, China, and Australia.

The largest peridot deposits in the world are found in the following locations:

Zabargad Island, Egypt: This island in the Red Sea is known for its large peridot crystals. The peridot mines on Zabargad Island were first worked by the ancient Egyptians, and they have been producing peridot for over 3,500 years.
Pakistan: Peridot is also found in Pakistan, in the Kohistan region. The peridot crystals from Pakistan are typically smaller than those found on Zabargad Island, but they are often of higher quality.
Myanmar: Peridot is also found in Myanmar, in the Mogok region. The peridot crystals from Myanmar are typically very high quality, and they are often used in fine jewelry.
United States: Peridot is also found in the United States, in the state of Arizona. The peridot mines in Arizona are the largest in the Western Hemisphere.

Natural peridot crystal with rare rutile inclusion – gem-quality olivine specimen featuring needle-like titanium dioxide crystals.

History and Uses of Peridot

Peridot has been prized for centuries. It was one of the most popular gemstones in ancient Egypt, and it was often used in jewelry and amulets. Peridot was also known as the "gem of the sun" because it was believed to have protective powers against the sun's rays.

Island of Zabargad: Zabargad, an island in the Red Sea, was a historically significant source of peridot. The ancient Egyptians mined peridot from this island.

Hawaii: In modern times, Hawaii has become a significant source of peridot. The gemstone is found in the volcanic basalt rocks of the island of Oahu.

Jewelry

The primary use of peridot is in jewelry, where it is often faceted and used in rings, necklaces, earrings, and bracelets.
It is appreciated for its vibrant green color, which ranges from yellowish-green to olive-green.

Historical and Cultural Significance: Due to its historical significance, peridot is sometimes used in antique or vintage jewelry designs, reflecting the charm and allure of bygone eras.

Cleopatra's Mines Collection: The mines on Zabargad Island are considered legendary due to their historical association with Cleopatra. The allure of peridot from these mines adds to the gemstone's mystique.

Hawaiian Jewelry: In Hawaii, peridot is often used in traditional jewelry designs, celebrating its connection to the volcanic origins of the islands.

Anniversary Gemstone: Peridot is the birthstone for the month of August and is associated with the 16th wedding anniversary.

Collector's Gemstone: Exceptional and rare peridot specimens, especially those with large, vibrant colors, can be highly sought after by gemstone collectors.

Care and Maintenance

Peridot is a relatively easy gemstone to care for. It should be cleaned with warm, soapy water and a soft cloth. Peridot should not be exposed to harsh chemicals or heat, as this can damage the gemstone.

Peridot crystal cluster from Spat Mine, Pakistan.
Photo: Fayyaz Ahmed

Meaning and Symbolism of Peridot

Peridot is associated with many meanings and symbols.

Prosperity and Abundance: Its resemblance to money's color led many cultures to associate peridot with wealth, fortune, and success.
Peace and Harmony: Its calming green hue is often linked to inner peace, balance, and emotional well-being. It's believed to soothe anxieties and promote relaxation.
Renewal and Growth: Peridot's connection to nature symbolizes new beginnings, personal growth, and positive change. It's thought to inspire creativity and help overcome challenges.
Love and Compassion: The gemstone is associated with the heart chakra, representing love, empathy, and healthy relationships. It's believed to foster kindness and understanding.
August Birthstone: Peridot is the official birthstone for August, making it a meaningful gift for those born in that month.
16th Anniversary Gemstone: It's also traditionally given to celebrate the 16th year of marriage, symbolizing growth and renewal within the relationship.

Vivid green peridot (gem-quality olivine) crystals in Canary Islands basalt, Spain.

Pricing and Value

The value of peridot is determined by four factors: color, clarity, size, and cut.

Color: The most valuable peridots have a deep green color with no yellow or brown tint.
Clarity: The fewer inclusions a peridot has, the more valuable it is. Inclusions are small, natural imperfections in the stone.
Size: Larger peridots are more valuable than smaller ones.
Cut: The cut of a peridot can also affect its value. A well-cut peridot will sparkle and reflect light beautifully.

Peridot is a relatively affordable gemstone, but high-quality peridots can be quite expensive.

The price of peridot can vary widely depending on the factors listed above. A small, low-quality peridot may cost only a few dollars, while a large, high-quality peridot can cost thousands of dollars.

Olivine vs. peridot: Key differences between the mineral group (Mg,Fe)₂SiO₄ and its gem-quality green variety.

Olivine Vs Peridot

Olivine: This is a group of silicate minerals, meaning they're formed from silicon and oxygen combined with other elements. Olivine itself comes in a variety of colors, typically green or yellow-green, but also brownish. It's a fairly common mineral found in volcanic rocks and meteorites.

Peridot: Peridot is actually a specific type of olivine. It refers to the gem-quality version of olivine, prized for its beautiful yellow-green to lime green color. Not all olivine is transparent or has the clarity needed for jewelry, so only that specific type gets called peridot.

Pallasite Meteorites

Large green peridot olivine crystals embedded in a pallasite meteorite’s iron-nickel matrix.
Photo: Steve Jurvetson

Pallasite meteorites are a type of stony-iron meteorite that contain large crystals of olivine/Peridot, a mineral that is often green in color. The green color of the olivine in pallasite meteorites is caused by the presence of iron impurities. The largest known peridot crystal found in a pallasite meteorite is about 2.5 centimeters in diameter.

Rough dark green peridot crystals (gem-quality forsterite).
Photos: Barlocher Federico

Peridot is a beautiful, versatile gemstone with a rich history and symbolism. It is a popular choice for jewelry, and it is also said to bring good luck and happiness. If you are looking for a gemstone that is both beautiful and meaningful, peridot is a great option.