The December birthstone, turquoise, is a captivating gemstone known for its vivid blue to green hues and its long-standing cultural and symbolic importance. This article delves into the rich history, geological properties, cultural significance, and modern uses of turquoise, drawing from a variety of sources to provide a comprehensive overview of this treasured stone.
Introduction
Turquoise is a hydrated phosphate of aluminum and copper, forming in the oxidized zones of copper deposits. It has been cherished for thousands of years and is one of the few gemstones with a history that spans across multiple ancient civilizations. As the birthstone for December, turquoise holds a unique place in both the world of gemology and cultural traditions. This article explores the gemstone's origins, its physical and chemical properties, its role in history and mythology, and its contemporary appeal in jewelry and fashion.
History and Lore
Turquoise has a rich and storied history that dates back to ancient times. It was one of the first gemstones to be used in jewelry, with evidence of its use found in archaeological sites across the globe.
One of the earliest known uses of turquoise was by the ancient Egyptians, who believed it had protective powers and used it in amulets and burial items. The Egyptians also believed that turquoise brought happiness and a long life. Cleopatra, one of the most famous Egyptian queens, was known to wear turquoise in her jewelry.
In the Americas, turquoise was highly valued by Native American tribes, particularly the Navajo, Hopi, and Zuni. These cultures used turquoise in jewelry, ceremonial objects, and even in trade with other tribes. The stone was considered a sacred object and was often associated with the sky and water. It was believed to bring good luck, healing, and protection.
In Asia, especially in Persia (modern-day Iran), turquoise was highly prized and was used to inlay in metalwork and ceramics. Persian artisans developed techniques for embedding turquoise in silver, a style that continues to influence jewelry design today.
The name "turquoise" comes from the French word turque, meaning "Turkish," as the stone was brought to Europe through Turkey by traders. In medieval Europe, turquoise was believed to have protective and healing properties and was used in various forms of jewelry and amulets.
Geological Formation and Sources
Turquoise is formed when copper-rich solutions seep into the pore spaces of existing rocks, such as sandstone, and deposit the mineral. The presence of water and oxygen is essential for the formation of turquoise, which gives the stone its characteristic blue to green color. The color variation is due to the presence of different impurities and the amount of water in the stone.
The most famous sources of turquoise are in the United States, particularly in the southwestern states of New Mexico, Arizona, and Nevada. These regions have produced some of the finest and most valuable turquoise in the world. Other notable sources include China, Iran, Egypt, and Mexico. Each source produces turquoise with slightly different color and quality characteristics.
In the United States, the Cerrillos Hills near Madrid, New Mexico, are one of the oldest known sources of turquoise. In Nevada, the Royston mine is known for producing high-quality turquoise that is often described as having a rich, even blue color with minimal matrix (the darker veins of host rock that appear in the turquoise).
Iran has a long history of turquoise mining and is known for producing turquoise with a deep blue color and minimal matrix. This stone is often referred to as "Persian turquoise" and is highly prized in the gemstone market.
The mining of turquoise is typically done by hand, as the stone is relatively soft and requires careful extraction to avoid damage. Once mined, turquoise is often stabilized to improve its durability and color. Stabilization involves impregnating the stone with resins or other substances to fill in the pores and make it more suitable for jewelry.
Gemological Properties
Understanding the gemological properties of turquoise is essential for anyone interested in this gemstone, whether as a collector, jewelry buyer, or gemology student. The key characteristics of turquoise include its color, hardness, luster, and specific gravity.
Color is the most important factor in determining the value of turquoise. The most desirable colors are deep, even blues with minimal matrix. Turquoise can range from light blue to greenish-blue, with the presence of matrix adding character and uniqueness to each piece. The color variation is due to the presence of copper (which gives the blue) and iron (which contributes to the greenish tones).
Turquoise has a hardness of 5 to 6 on the Mohs scale, which makes it relatively soft compared to other gemstones. This means that it requires careful handling and is not suitable for everyday wear without proper care. The stone also has a waxy to greasy luster, which can be enhanced through polishing.
The specific gravity of turquoise ranges from 2.6 to 2.8, and it has a refractive index that is typically between 1.61 and 1.65. These properties help gemologists identify turquoise and distinguish it from other blue stones.
One of the most important aspects of turquoise is its porosity and susceptibility to staining and discoloration. The stone can absorb oils, dirt, and other substances, which can affect its color and appearance. For this reason, turquoise is often stabilized before being used in jewelry.
Stabilization is a process that involves impregnating the stone with resins or other substances to fill in the pores and improve its durability. Stabilized turquoise is more stable and easier to clean, making it a better choice for jewelry. However, some purists prefer to use natural turquoise, which has not been stabilized, for its authenticity and unique character.
Symbolism and Metaphysical Beliefs
Turquoise has been associated with a wide range of symbolic meanings and metaphysical beliefs throughout history. In ancient cultures, it was believed to have protective and healing properties. The stone was often used in amulets and talismans to ward off evil, bring good luck, and promote health and longevity.
In Native American cultures, turquoise was considered a sacred stone that represented the sky and water. It was used in ceremonial objects and jewelry and was believed to bring good fortune and protection. The Navajo, for example, used turquoise in their sand paintings and believed it to have healing powers.
In the Middle East and Asia, turquoise was also believed to have protective and healing properties. It was used in amulets and talismans to ward off the evil eye and to promote health and vitality. In some cultures, it was believed that turquoise could help with communication and encourage honest and clear speech.
In modern times, turquoise is still associated with a range of symbolic meanings. It is often seen as a stone of protection, especially for travelers. It is also believed to promote emotional balance and to help with communication and self-expression. Some people believe that turquoise can help with physical healing and is particularly useful for treating ailments related to the throat, lungs, and digestive system.
Care and Cleaning
Due to its relatively soft nature and porosity, turquoise requires special care to maintain its beauty and durability. Proper care and cleaning can help preserve the stone's color and appearance for years to come.
When cleaning turquoise, it is important to avoid using harsh chemicals, abrasive cleaners, or ultrasonic cleaners. These can damage the stone and cause it to lose its color or become stained. Instead, a gentle cleaning method is recommended.
To clean turquoise, use a soft cloth or a soft-bristled brush and a mild soap or a solution of warm water and a few drops of dish soap. Gently wipe the stone with the cloth or brush to remove dirt and debris. After cleaning, rinse the stone with lukewarm water and pat it dry with a soft cloth.
It is also important to avoid exposing turquoise to excessive heat, direct sunlight, or harsh chemicals. These can cause the stone to become brittle, discolored, or damaged. When storing turquoise jewelry, keep it in a cool, dry place away from other jewelry to prevent scratches and damage.
When wearing turquoise, it is advisable to avoid activities that could cause the stone to chip or crack. While stabilized turquoise is more durable, it is still relatively soft compared to other gemstones and requires careful handling.
Conclusion
Turquoise is a gemstone with a rich history, beautiful colors, and a wide range of symbolic meanings. From its early use in ancient Egypt and Native American cultures to its modern popularity in jewelry and fashion, turquoise continues to captivate and inspire. Its unique properties and cultural significance make it a valuable and meaningful addition to any collection.
Whether worn as a birthstone for December, a symbol of protection, or simply for its beauty, turquoise remains a timeless and treasured gemstone. Understanding its history, properties, and care requirements can help ensure that this beautiful stone continues to be appreciated and enjoyed for generations to come.