The geological story of peridot is as compelling as its history. Peridot is the gem-quality variety of olivine, a silicate mineral with the chemical formula (Mg, Fe)₂SiO₄. The green color, which can range from a light, yellowish-green to a deep olive, is determined by the amount of iron present in the crystal structure; a higher iron content results in a deeper green. What makes peridot geologically unique is its origin. While most gemstones are formed in the Earth's crust, peridot crystals are formed deep within the Earth's mantle, at depths of 20 to 55 miles (32 to 88 kilometers). These crystals are then brought to the surface by volcanic activity. In some rare and remarkable instances, peridot crystals have been found in meteorites that have fallen to Earth, making them truly extraterrestrial gems. This origin story contributes to its mystique and is a point of fascination for gemologists and collectors alike. Major sources for peridot include Arizona in the United States, as well as Pakistan, Myanmar, and China, each producing stones with slightly different characteristics based on their specific geological conditions.
From a gemological perspective, peridot possesses a set of properties that make it both beautiful and durable for jewelry, though it requires some care. It rates a 6.5 to 7 on the Mohs scale of hardness, which means it is moderately hard and resistant to scratching but can be susceptible to chipping or breaking if struck with sufficient force. Its toughness is generally considered to be fair to good. Peridot has no cleavage, which is a benefit, as it means it will not break along flat planes when subjected to pressure. However, it has parting, which is a tendency to split along planes that are not natural cleavage planes. The gem's refractive index is relatively low for a colored stone, and it is strongly doubly refractive, a property that can be used by gemologists for identification. Its specific gravity also varies depending on its iron content. In terms of clarity, peridots are often found with inclusions, but high-quality gems with good clarity are available. The most prized color is considered to be a rich, pure green with no hint of yellow or brown. The gem is typically cut into standard shapes like rounds, ovals, and cushions to maximize its color and brilliance.
Peridot has accumulated a wealth of symbolism and metaphysical beliefs throughout its long history. The ancient Egyptians revered it as the "gem of the sun," believing it offered protection and warded off evil. It was thought to have the power to heal sickness and was often worn as an amulet. Some historical accounts suggest that the famous emeralds of Cleopatra might have actually been peridots, as some of the stones from ancient Egyptian mines were misidentified as emeralds for centuries. In medieval times, peridot was brought to Europe by the Crusaders and was used to ornament churches and religious objects. It was often set in gold and was believed to have the power to dispel darkness and fear. In modern crystal healing traditions, peridot is associated with prosperity, good fortune, and emotional well-being. It is said to bring joy, openness, and a sense of renewal to its wearer. As the birthstone for August, it is believed to bring peace, health, and rest, and is also associated with the zodiac sign Leo. Its bright, positive energy is thought to help one let go of past burdens and embrace new growth.
Caring for peridot jewelry requires an understanding of its physical properties. While it is durable enough for everyday wear in rings, earrings, or pendants, its moderate hardness and parting characteristics mean it should be handled with some care. It is best to store peridot jewelry separately from other gems and metals to prevent scratching. When cleaning, warm, soapy water and a soft brush are the most effective and safest methods. It is crucial to avoid ultrasonic cleaners and steam cleaning, as the sudden temperature changes and vibrations can damage the stone, especially if it has any fractures or inclusions. Chemicals, including harsh detergents and acids, should also be avoided as they can dull or damage the gem's surface. With proper care, a peridot gemstone can remain a vibrant and cherished piece for generations, its green fire a constant reminder of the volcanic and cosmic forces that brought it into being. Its status as the primary August birthstone ensures its continued popularity and significance in the world of gemstones.
Conclusion
Peridot is a gemstone of remarkable origin and enduring appeal. Its formation deep within the Earth's mantle and its delivery to the surface through volcanic activity make it a geological marvel. As the primary birthstone for August, its vibrant green color, reminiscent of the sun, connects it to a rich history of reverence and use, from ancient Egyptian amulets to modern jewelry. Its gemological properties, including its chemical composition as a variety of olivine and its moderate hardness on the Mohs scale, define both its beauty and its care requirements. The symbolic meanings attributed to peridot—protection, prosperity, and renewal—add layers of cultural significance to its physical attributes. For those born in August, peridot offers a link to a deep and luminous past, a gem formed by the fiery heart of the planet and celebrated for its unique and captivating light.