The star ruby, a captivating variety of the mineral corundum, holds a prominent place in the world of gemstones. Recognized as the birthstone for July, and celebrated as the stone for the 15th, 40th, and 80th anniversaries, it is prized for its unique optical phenomenon known as asterism – the display of a six-rayed star. This article will delve into the gemological properties, historical significance, and care of the star ruby, drawing exclusively from available sources.
History and Lore
While the sources do not provide extensive historical details regarding the star ruby’s early use, they establish its enduring appeal as a gemstone of significance. The association with the month of July and specific wedding anniversaries underscores its symbolic value. The sources do not detail ancient beliefs surrounding the ruby, but its modern recognition as a gemstone of passion, protection, and prosperity is implied through its continued use in jewelry.
Geological Formation and Sources
The formation of star rubies is a fascinating geological process. These gems are formed under specific conditions within metamorphic rocks. The characteristic star effect is caused by the presence of microscopic, needle-like inclusions of rutile, known as “silk,” arranged in intersecting patterns within the corundum crystal. These rutile needles reflect light, creating the star-like appearance when the stone is cut into a smooth, domed cabochon.
The sources do not specify particular mining locations for star rubies, but they do indicate that rubies, in general, are widely sold globally.
Gemological Properties
Star rubies possess distinct gemological properties that contribute to their value and desirability. According to the provided sources, star rubies register a 9 on the Mohs scale of hardness, placing them second only to diamonds in terms of durability. This exceptional hardness makes them suitable for everyday wear. They also exhibit “excellent” toughness, meaning they are resistant to chipping and abrasion.
The refractive index of star rubies falls within the range of 1.762-1.770 (+.009, -.005), and their specific gravity is approximately 4.00 (+.10,-.05). These properties are crucial for gemologists in identifying and authenticating star rubies.
The defining characteristic of a star ruby is, of course, asterism. This effect is best observed when the stone is illuminated with a single light source, causing the star to appear to move across the surface as the light source is shifted. The quality of the star – its sharpness, intensity, and symmetry – significantly impacts the gem’s value. The sources emphasize that the rutile needles responsible for asterism must remain intact to preserve the star effect; heat treatment can dissolve these needles, diminishing the stone’s worth.
Confusion with Other Gemstones
Historically, red gemstones have often been misidentified. The sources highlight a notable case of confusion between red spinel and ruby. Remarkable examples of this misidentification include the “Black Prince’s Ruby” and the “Timur Ruby,” both prominent stones in the British Crown Jewels, which were later determined to be red spinels. The Kremlin Museum in Moscow also houses a large red spinel previously believed to be a ruby, and the Crown Jewels of Iran contain a dazzling collection of red spinels. This historical confusion underscores the importance of accurate gemological identification.
Sapphire and its Varieties
While the focus is on the star ruby, the sources also provide information on sapphire, a closely related gemstone. Sapphire, like ruby, is a variety of corundum. Blue sapphire is the traditional birthstone for September, but sapphire also occurs in white, pink, and yellow colors, serving as alternate birthstones for April, October, and November, respectively. Sapphire shares the same hardness (9 on the Mohs scale) and refractive index (1.762-1.770) as ruby, making it equally durable and desirable for jewelry. Sapphire and ruby together account for more than half of all gemstones sold worldwide.
Care and Cleaning
Maintaining the beauty of star ruby jewelry requires proper care. The sources recommend cleaning star rubies with a soft brush and jewelry cleaner or warm, soapy water. This gentle cleaning method helps remove dirt and grime without damaging the stone or its delicate rutile inclusions. Avoid harsh chemicals or ultrasonic cleaning, as these can potentially harm the gem.
Modern Jewelry and Customization
The sources showcase a variety of modern jewelry incorporating birthstones, including star rubies. Options range from personalized heart birthstone rings in sterling silver with CZ accents to custom necklaces and bracelets featuring birthstones and initials. The availability of customized designs allows individuals to create unique pieces that reflect their personal style and commemorate special occasions. The sources list several examples of birthstone jewelry, including necklaces with customized name plates, infinity pendants, and druzy necklaces.
Other Gemstones and Birthstone Associations
The provided sources briefly mention other gemstones and their birthstone associations. Tanzanite, a blue variety of zoisite found only in Tanzania, is a birthstone for December. Tiger’s-eye, a quartz variety known for its silky luster, is also mentioned, along with tourmaline and topaz, which come in a variety of colors. These gemstones, like the star ruby, offer a diverse range of options for jewelry and personal adornment.
Conclusion
The star ruby, with its captivating asterism and exceptional durability, remains a highly sought-after gemstone. As the birthstone for July and a symbol of significant anniversaries, it carries a rich history and enduring appeal. Its unique formation, requiring specific geological conditions and the presence of rutile inclusions, contributes to its rarity and value. Proper care and cleaning will ensure that the beauty of a star ruby continues to shine for generations. The historical confusion with red spinel serves as a reminder of the importance of accurate gemological identification, while the broader context of sapphire and other birthstones highlights the diverse and fascinating world of gemstones.