Spinel, often mistaken for other gemstones, possesses a captivating beauty and a history intertwined with those of more famous gems like ruby. While not always receiving the recognition it deserves, spinel is a durable and attractive gemstone in its own right, offering a wide range of colors and a fascinating geological origin. This article will explore the history, gemological properties, sources, and significance of spinel, drawing solely from available sources.
History and Lore
Though not explicitly detailed with ancient lore comparable to rubies, spinel’s history is closely linked to that of its more celebrated counterparts. For centuries, red spinel was often confused with ruby, particularly in historical contexts where gemological understanding was less refined. The sources indicate that red spinel, like ruby, derives its color from the presence of traces of chromium. This similarity in appearance led to spinel being included amongst the gems adorning significant historical artifacts.
The sources do not detail specific historical events or cultural beliefs directly associated with spinel itself, but rather highlight its role as a substitute for ruby. This substitution was practical, as spinel’s hardness (8 on the Mohs scale) is only slightly less than that of ruby, and its brilliance is comparable. Furthermore, spinel is more plentiful than ruby, making it a more affordable alternative.
Geological Formation and Sources
Spinel is an oxide of magnesium and aluminum, distinct in its composition from ruby, which is a variety of corundum. The sources detail spinel’s occurrence in various locations, including Ceylon (modern-day Sri Lanka) and Burma (modern-day Myanmar). Specifically, stones from Burma are noted alongside those from Ceylon, with examples weighing 30 to 36 carats. The sources also mention spinel originating from Ceylon, with examples weighing 22 and 30 carats.
The sources do not provide a detailed account of spinel’s formation processes, but they do indicate that it is found in gem gravels, as exemplified by Ceylon stones. The sources also mention that synthetic spinel is widely used as a substitute for aquamarine and other gems, indicating a capacity for laboratory creation.
Gemological Properties
Spinel boasts impressive gemological properties that contribute to its desirability as a gemstone. Its hardness of 8 on the Mohs scale makes it a durable stone suitable for everyday wear. The sources highlight that spinel’s brilliance is approximately equal to that of ruby, making it a visually appealing gem.
Spinel exhibits a wide range of colors, rivaling those of tourmaline in subtlety. While red spinel is perhaps the most well-known due to its historical confusion with ruby, spinel also occurs in blue, green, yellow, and even colorless varieties. Interestingly, completely colorless spinel appears to exist only as a synthetic material. The sources do not provide specific refractive index or dispersion values for spinel.
Spinel as a Gemstone Substitute
A significant aspect of spinel’s gemological profile is its role as a substitute for other, more expensive gemstones. Synthetic blue spinel is commonly used as a substitute for aquamarine. Synthetic spinels of various colors are also employed as substitutes for many other gems. However, the sources note that synthetic stones often lack the subtle shades characteristic of natural spinel. Despite its utility as a substitute, spinel is also valued as a fine gemstone in its own right, owing to its hardness, durability, and attractive colors.
Other Rarer Gemstones
The sources briefly mention a number of other rarer minerals that can produce gemstones, including cordierite, benitoite, euclase, phenakite, and several others. These gems, like spinel, are often less well-known than the more popular varieties. Willemite, a zinc silicate found in Franklin, New Jersey, is highlighted as an example of a rare mineral that has produced some gemmy crystals, though its borderline hardness and extreme rarity limit its presence in the gem market.
Chrysoberyl and its Relationship to Spinel
The sources draw a comparison between spinel and chrysoberyl, noting that both are closely related in terms of chemical composition. Chrysoberyl is a beryllium aluminate, while spinel is a magnesium aluminate. Both minerals can exhibit attractive colors and are valued as gemstones. Chrysoberyl also has a cat’s-eye variety, exemplified by the 58-carat Maharani from Ceylon, and an alexandrite variety, known for its color-changing properties.
Conclusion
Spinel is a captivating gemstone with a rich history, often overshadowed by its resemblance to ruby. Its durability, brilliance, and wide range of colors make it a desirable gem in its own right. While historically used as a substitute for more expensive stones, spinel is increasingly recognized and appreciated for its unique qualities. The sources highlight its geological origins in locations like Ceylon and Burma, and its chemical composition as an oxide of magnesium and aluminum. Spinel’s story is a testament to the beauty and complexity of the natural world, and its enduring appeal to gem enthusiasts and collectors alike.