The month of September is uniquely associated with two distinct and celebrated birthstones: sapphire and lapis lazuli. This duality offers individuals born in this autumn month a choice between two gems with vastly different compositions, histories, and aesthetic appeals. Sapphire, renowned for its deep, velvety blue and exceptional durability, is one of the world's most coveted precious stones. Lapis lazuli, a rock prized for its vibrant, celestial blue color flecked with golden pyrite, has captivated civilizations for millennia as a symbol of royalty and spiritual insight. This article explores the geological origins, gemological properties, historical lore, and cultural significance of both September birthstones, drawing upon available information to provide a comprehensive guide for enthusiasts and collectors.
The choice between sapphire and lapis lazuli reflects a preference for either a hard, brilliant gemstone suitable for everyday wear or a softer, opaque material rich with historical narrative. While sapphire is a mineral (corundum) valued for its clarity and color, lapis lazuli is an aggregate of several minerals, primarily lazurite, valued for its intense, uniform hue. Understanding the distinct characteristics of each stone is essential for appreciating their roles as September's birthstones.
Sapphire: The Celestial Blue Stone
Sapphire is a variety of the mineral corundum (aluminum oxide, Al₂O₃), with its iconic blue color derived from trace amounts of iron and titanium. As a member of the corundum family, it shares the same base mineral as ruby, differing only in its coloration. Sapphire is celebrated for its exceptional hardness, ranking 9 on the Mohs scale, making it second only to diamond in durability. This resilience, combined with its brilliant luster and deep color, has made sapphire a perennial favorite for fine jewelry, particularly engagement rings and heirloom pieces.
Geological Formation and Sources
Sapphire forms under high-temperature and high-pressure conditions in metamorphic rocks and certain igneous environments. The world's most significant sapphire deposits are geographically diverse, reflecting the gem's global appeal. Historically, the Kashmir region of the Indian subcontinent was famed for producing the finest "cornflower blue" sapphires, though these mines are largely depleted. Sri Lanka (Ceylon) remains a major source of high-quality sapphires, known for their lighter, brighter blues. Other notable sources include Myanmar (Burma), Thailand, Cambodia, and Australia. In recent decades, East Africa, particularly Tanzania and Madagascar, has emerged as an important producer of sapphire, often yielding stones with unique color variations, including vivid blues and fancy colors like yellow and green.
The formation of sapphire requires specific geological conditions. In metamorphic settings, aluminum-rich rocks are subjected to intense heat and pressure, allowing corundum crystals to grow. In igneous environments, sapphire can crystallize from magma, often found in rocks like basalt. The presence of certain trace elements during crystallization determines the final color of the gemstone.
Gemological Properties
Sapphire is prized for a combination of physical and optical properties that make it both beautiful and durable. Its key characteristics include:
- Hardness: 9 on the Mohs scale, making it extremely resistant to scratching and suitable for daily wear.
- Crystal System: Trigonal.
- Refractive Index: 1.762 to 1.770, giving it a high degree of brilliance.
- Specific Gravity: 3.95 to 4.03, indicating a dense stone.
- Chemical Composition: Aluminum oxide (Al₂O₃) with trace impurities.
- Color: The most sought-after color is a deep, velvety "royal blue," but sapphire occurs in every color of the rainbow except red (which is classified as ruby). The color is caused by the presence of trace elements like iron and titanium.
- Clarity: Sapphires are typically included, with inclusions common. However, the finest gems are eye-clean. Some inclusions, like fine silk (rutile needles), can create a soft, velvety texture in the stone or cause asterism (a star effect) in star sapphires.
The value of a sapphire is determined by the "4 Cs": color, clarity, cut, and carat weight. Color is the most critical factor, with the most valuable stones exhibiting a rich, medium to medium-dark blue with strong saturation and a velvety texture.
Symbolism and Metaphysical Beliefs
Sapphire has been imbued with profound symbolism throughout history. In ancient Persia, it was believed that the earth rested on a giant sapphire, and its reflection colored the sky blue. The Greeks and Romans associated sapphire with Apollo, the god of prophecy, and wore it as a talisman for wisdom and protection. During the Middle Ages, the clergy wore sapphire to symbolize heaven and divine favor, and it was thought to protect against envy and poison.
In metaphysical traditions, sapphire is considered a stone of wisdom and truth. It is believed to enhance mental clarity, focus, and spiritual insight, making it a favored stone for meditation. It is also associated with the throat and third eye chakras, promoting clear communication and intuition. As a birthstone, sapphire is linked to loyalty, trust, and sincerity, making it a popular choice for commitment jewelry.
Care and Cleaning
Due to its exceptional hardness, sapphire is relatively easy to care for. It can be cleaned with warm, soapy water and a soft brush. Ultrasonic cleaners are generally safe for untreated sapphire, but caution is advised for stones that have been fracture-filled or heat-treated, as the vibrations may damage the treatment. Steam cleaning is also acceptable for most sapphires. The primary risk to sapphire is impact; while hard, it is not indestructible and can chip if struck against a hard surface.
Lapis Lazuli: The Stone of Heaven
Lapis lazuli is not a single mineral but a metamorphic rock composed primarily of the mineral lazurite (a complex sodium aluminosilicate containing sulfur and calcium), along with calcite (white veins) and pyrite (golden flecks). Its intense, uniform blue color, caused by the presence of sulfur in the lazurite crystal structure, has made it one of the most recognizable opaque gems in history. Unlike sapphire, lapis lazuli is prized for its color and pattern rather than transparency or brilliance.
Geological Formation and Sources
Lapis lazuli forms under specific metamorphic conditions, typically in limestone or marble deposits that have been subjected to contact metamorphism. The most significant and historically important source is the Sar-i Sang mines in the Badakhshan province of Afghanistan, which have been operational for over 6,000 years. This region produced the finest, most vibrant blue lapis, often called "Afghan lapis." Other sources include Chile (the Caracoles mines), Russia (the Lake Baikal region), and smaller deposits in Myanmar and the United States.
The formation process involves the interaction of fluids rich in sodium, aluminum, silicon, and sulfur with carbonate rocks. Over time, these elements recrystallize to form lazurite, with calcite and pyrite incorporated as impurities. The quality of lapis lazuli is judged by its color intensity and the distribution of calcite and pyrite. The finest stones have a deep, even blue color with minimal white calcite veins and evenly distributed golden pyrite specks.
Gemological Properties
Lapis lazuli has a very different set of properties from sapphire, reflecting its composite nature. Its key characteristics include:
- Hardness: 5 to 5.5 on the Mohs scale, making it relatively soft and susceptible to scratching.
- Luster: Vitreous to greasy, often appearing waxy when polished.
- Specific Gravity: 2.7 to 3.0, less dense than many gemstones.
- Composition: Primarily lazurite (25-40%), with calcite and pyrite.
- Color: Deep, celestial blue, sometimes with a hint of violet.
- Transparency: Opaque; no transparency or light penetration.
The value of lapis lazuli is determined by the intensity and uniformity of its blue color. Stones with a rich, even "ultramarine" blue and minimal white or brown calcite inclusions command the highest prices. The presence of golden pyrite specks is often considered desirable, adding to the stone's visual interest, though too much pyrite or calcite can lower its value.
History and Lore
Lapis lazuli is one of the oldest gems in human history, with archaeological evidence of its use dating back to the Neolithic period. It was a favorite of ancient Egyptian pharaohs, who used it in jewelry, amulets, and the famous funeral mask of Tutankhamun. In Mesopotamia, it was used in cylinder seals and inlay. The stone was also highly valued in the Islamic world and medieval Europe.
Perhaps its most famous historical application was as a pigment. Ground lapis lazuli, known as ultramarine, was the most precious pigment in Renaissance art, used to depict the robes of the Virgin Mary. Its cost was so high that it was reserved for the most important subjects. The pigment was made by grinding the stone, separating the lazurite, and mixing it with a binder.
Symbolism and Metaphysical Beliefs
Lapis lazuli has long been associated with royalty, wisdom, and truth. In ancient Egypt, it was linked to the goddess Isis and was believed to provide protection and guidance in the afterlife. The Greeks and Romans associated it with the heavens and the power of the gods.
In metaphysical beliefs, lapis lazuli is considered a powerful stone for enhancing intuition and spiritual awareness. It is said to stimulate the third eye and throat chakras, promoting psychic abilities and honest communication. It is also believed to relieve stress and bring peace and harmony. As a birthstone, it is thought to encourage self-expression and authenticity.
Care and Cleaning
The softness and porous nature of lapis lazuli require careful handling. It should be protected from scratches, chemicals, and heat. Cleaning should be done with a soft, damp cloth and mild soap. Avoid ultrasonic cleaners, steam, and harsh chemicals, as they can damage the stone. Lapis lazuli can be porous and may absorb oils and liquids, which can alter its color over time.
Comparing the September Birthstones
The choice between sapphire and lapis lazuli for a September birthstone gift or personal jewelry is a matter of personal preference, lifestyle, and desired symbolism. The following table summarizes their key differences:
| Feature | Sapphire | Lapis Lazuli |
|---|---|---|
| Mineral Family | Corundum (mineral) | Rock (aggregate of lazurite, calcite, pyrite) |
| Hardness (Mohs) | 9 (Very Hard) | 5-5.5 (Soft) |
| Color | Transparent blue (or other colors) | Opaque deep blue with white/gold specks |
| Durability | Excellent for daily wear | Suitable for occasional wear, requires care |
| Primary Sources | Sri Lanka, Myanmar, Madagascar, East Africa | Afghanistan, Chile, Russia |
| Historical Significance | Symbol of royalty, wisdom, and protection | Used in art (ultramarine pigment), ancient amulets |
| Metaphysical Beliefs | Enhances mental clarity and truth | Stimulates intuition and spiritual awareness |
Conclusion
Sapphire and lapis lazuli, though both assigned to the month of September, represent two distinct paths in the world of gemstones. Sapphire, with its unmatched hardness and brilliant transparency, embodies the qualities of a timeless precious gem, favored for its durability and regal beauty. Lapis lazuli, an opaque rock with a history as deep as its color, offers a connection to ancient civilizations and the celestial realm through its vibrant hue and golden flecks. Whether one is drawn to the enduring brilliance of sapphire or the profound history of lapis lazuli, both stones provide a meaningful and beautiful link to the month of September, celebrating individuality and the rich tapestry of gemological heritage.