Sapphire, the birthstone of September, holds a prominent place in the world of gemstones, celebrated for its rich history, diverse colors, and remarkable durability. While most readily recognized in its classic blue hues, sapphire encompasses a spectrum of colors, with red corundum being known as ruby. This article delves into the geological origins, historical significance, gemological properties, and modern applications of this captivating gem, drawing solely from available sources.
History and Lore
Sapphires boast a history stretching back millennia. Evidence suggests their use as early as 957 BCE, featuring among the twelve precious stones adorning the High Priest’s breastplate in the First Temple. The exact origins of sapphire discovery remain unknown, lost to the depths of antiquity. Throughout history, sapphires have been associated with royalty, wisdom, and virtue. Medieval Europeans attributed healing powers to the stone, believing it could cure plague boils and eye diseases, and even serve as an antidote to poison.
More recently, notable sapphires have captured public imagination. The Rockefeller Sapphire, a 62.02-carat rectangular step-cut stone originating from Myanmar (Burma), was acquired by John D. Rockefeller, Jr. in 1934. Another famous example is the 12-carat blue sapphire surrounded by diamonds, initially worn by Princess Diana and later given to Kate Middleton, Duchess of Cambridge. These iconic gems exemplify the enduring appeal and value of sapphire.
Geological Formation and Sources
Sapphire is a variety of corundum, an aluminum oxide with the chemical formula Al2O3. Its crystal structure is hexagonal, characterized by four axes, three of equal length intersecting at 60-degree angles, and one of unequal length intersecting at a right angle. Sapphires form in metamorphic and igneous rocks, requiring specific geological conditions to develop their characteristic color and clarity.
Historically significant sources of sapphire include Kashmir, a mountainous region in northern India bordering Pakistan, Myanmar (Burma), and Sri Lanka. These locations are renowned for producing sapphires of exceptional quality and color. However, significant quantities have also been found in Australia, Thailand, Cambodia, Madagascar, the United States (Montana), and various other countries across Asia and Africa. Modern mining operations continue to yield sapphires from these and newly discovered locations, contributing to the global supply.
Gemological Properties
Beyond color, the gemological properties of sapphire are identical to those of ruby. Sapphire exhibits a remarkable hardness of 9 on the Mohs scale, making it exceptionally durable and suitable for everyday wear. This hardness is second only to diamond. The gem’s density and refractive index contribute to its brilliance and luster.
While blue is the most iconic color, sapphires occur in a wide range of hues, including pink, yellow, green, violet, and orange. Any corundum that is not red is classified as sapphire. Color zoning, characterized by colorless bands within the blue, is a common identifying feature. Sapphires can also exhibit optical phenomena such as asterism, known as the “star effect,” caused by intersecting needle-like inclusions of rutile. These inclusions, when properly oriented and cut en cabochon, create a six-rayed star pattern. In rare instances, twelve-rayed stars can occur due to the combination of rutile needles and hematite platelets. Another phenomenon, the cat's eye effect, can also be observed when the girdle plane of the cabochon is aligned with the crystal’s c-axis.
Sapphires may be found in their natural state or undergo heat treatment to enhance their color and clarity, a common practice within the gem industry. Both natural and heat-treated sapphires are considered beautiful and valuable.
Identifying Sapphires and Synthetic Variations
Identifying sapphires and determining their origin requires careful examination. Gemologists analyze inclusions, luminescence, and absorption spectra to distinguish natural sapphires from synthetic varieties. Characteristic inclusions can provide clues about a sapphire’s geographic origin. For example, specific inclusion patterns are associated with sapphires from different mining regions.
Synthetic sapphires, created in laboratories, often exhibit curved striae, a feature not found in natural stones. The presence of these striae can indicate a lab-grown origin. The arrangement of inclusions can also differentiate between natural and synthetic stones.
Symbolism and Metaphysical Beliefs
Throughout history, sapphire has been imbued with symbolic meaning. Beyond the medieval beliefs in its healing properties, sapphire has been associated with wisdom, loyalty, and nobility. The stone was believed to offer protection against poison and safeguard the wearer from harm. While specific metaphysical beliefs vary across cultures, sapphire is often considered a stone of spiritual enlightenment and inner peace.
Care and Cleaning
Due to its exceptional hardness, sapphire is a durable gemstone suitable for everyday wear. However, like all gemstones, it requires proper care to maintain its brilliance. Sapphires can be cleaned using warm, soapy water and a soft brush. Avoid harsh chemicals or abrasive cleaners, as these can damage the stone’s surface. Ultrasonic cleaners are generally safe for untreated sapphires, but caution should be exercised with heat-treated or fracture-filled stones. Regular cleaning will help preserve the sapphire’s luster and beauty for generations.
Modern Applications
While primarily valued for its beauty in jewelry, sapphire also possesses practical applications beyond adornment. Its exceptional hardness and durability make it ideal for creating high-durability windows, wristwatch crystals, and movement bearings. Furthermore, sapphire is utilized in various electronic applications due to its insulating properties and resistance to scratching.
Sapphire Prices
The cost of a sapphire varies significantly depending on several factors, including quality, treatment, color, cut, size, and shape. Prices can range from $20 per carat to $450 per carat, and even exceed hundreds of thousands of dollars for exceptional specimens. A small, high-quality sapphire can be more valuable than a larger stone of lower quality. Therefore, each sapphire must be evaluated individually to determine its true worth. The most expensive sapphires are typically those with exceptional color, clarity, and size, particularly those originating from historically significant locations like Kashmir.
Conclusion
Sapphire remains a highly prized and versatile gemstone, celebrated for its beauty, durability, and rich history. From its ancient origins as a symbol of royalty and healing to its modern applications in technology, sapphire continues to captivate and inspire. Its diverse range of colors, coupled with its exceptional physical properties, ensures its enduring appeal for generations to come. As the September birthstone, sapphire represents wisdom, loyalty, and nobility, making it a meaningful and cherished gem for those born under its radiant glow.