The allure of a birthstone extends beyond its aesthetic appeal; it’s a connection to history, tradition, and personal significance. However, a crucial aspect often overlooked when selecting a birthstone is its durability – its ability to withstand daily wear and maintain its beauty over time. This durability is scientifically measured using the Mohs Hardness Scale, a system that ranks a gemstone’s resistance to scratching. This article provides a comprehensive overview of birthstones and their corresponding rankings on the Mohs scale, offering insights into their suitability for various types of jewelry and providing guidance on proper care.
Understanding the Mohs Hardness Scale
Developed in 1812 by German mineralogist Friedrich Mohs, the Mohs Scale of Hardness is a comparative scale ranging from 1 to 10. A higher number indicates greater resistance to scratching. The scale is not linear; a diamond (hardness of 10) is not ten times harder than a topaz (hardness of 8). Instead, it’s based on the ability of one mineral to scratch another. For example, a mineral with a hardness of 7 will scratch a mineral with a hardness of 6, but will be scratched by a mineral with a hardness of 8. This scale is invaluable for both gemologists and jewelry buyers, providing a practical measure of a gemstone’s longevity and suitability for different applications.
Birthstone Hardness: A Month-by-Month Breakdown
Each month is associated with one or more birthstones, each possessing unique characteristics and a corresponding position on the Mohs scale. Understanding these rankings is essential for making informed choices when selecting birthstone jewelry.
January – Garnet (6.5–7.5)
Garnet, the birthstone of January, exhibits moderate durability. With a hardness ranging from 6.5 to 7.5, it is reasonably suitable for everyday wear, but caution should be exercised to avoid significant scratches or abrasions.
February – Amethyst (Quartz) (7)
Amethyst, a variety of quartz, boasts a hardness of 7 on the Mohs scale, classifying it as fairly durable. It can be cleaned with warm soapy water and a soft cloth or brush.
March – Aquamarine (7.5–8)
Aquamarine, a member of the beryl family, is a great choice for regular wear, possessing a hardness of 7.5 to 8. Its clarity and bright sparkle contribute to its popularity. Bloodstone, an alternate March birthstone, is a type of quartz found in various locations including India, Brazil, and Australia.
April – Diamond (10)
Diamond reigns supreme as the hardest known natural substance, achieving a perfect score of 10 on the Mohs scale. Its exceptional hardness makes it ideal for everyday wear and ensures its lasting brilliance. The name ‘Diamond’ originates from the ancient Greek word ‘adamas,’ meaning ‘invincible.’
May – Emerald (7.5–8, but brittle)
Emerald, another beryl variety, shares a hardness of 7.5–8 with aquamarine. However, emeralds are known to be brittle, meaning they are susceptible to chipping and fracturing despite their relatively high hardness. Careful handling is advised.
June – Pearl, Moonstone, Alexandrite (2.5–8.5)
June presents a diverse range of birthstones with varying degrees of durability. Pearls are exceptionally delicate, with a hardness of only 2.5–4, requiring meticulous care to avoid damage. Moonstone falls around 6 on the scale, making it less suitable for rings. Alexandrite, a rare color-changing gem, can reach a hardness of 8.5, offering greater durability.
July – Ruby (9)
Ruby, a variety of corundum, is exceptionally durable with a hardness of 9. Its rich history and iconic status make it a highly sought-after gemstone.
August – Peridot, Spinel (6.5–8)
August offers two birthstone options: peridot and spinel. Peridot, with a hardness of 6.5–7, requires medium care. Spinel, ranging up to a hardness of 8, offers greater durability.
September – Sapphire (9)
Sapphire, also a variety of corundum, shares ruby’s exceptional hardness of 9, making it ideal for everyday wear.
October – Opal, Tourmaline (5.5–6.5)
October birthstones, opal and tourmaline, exhibit moderate to low durability. Opal, with a hardness of 5.5–6.5, is delicate and requires careful handling. Tourmaline, while more diverse in properties, generally falls within the same range.
November – Citrine, Topaz (7–8)
November’s birthstones, citrine and topaz, are fairly durable. Citrine, a quartz variety, has a hardness of 7, while topaz ranges from 7 to 8. Topaz, however, possesses poor toughness and can be prone to chipping or cracking.
December – Blue Topaz, Tanzanite, Turquoise (5–8)
December offers a wide spectrum of durability with its three birthstones. Blue topaz, like regular topaz, has a hardness of 7-8 but requires careful handling. Tanzanite, a relatively recent addition to the birthstone list, is known for its deep indigo hue. Turquoise, ranging from 2.5 to 4.5, is extremely delicate and requires significant protection.
Gemstone Care Based on Hardness
The Mohs hardness scale provides a valuable guide for determining the appropriate care for each gemstone.
| Mohs Range | Recommended Care |
|---|---|
| 9–10 | Low maintenance, ideal for daily wear |
| 7–8 | Moderate care; avoid abrasives |
Softer gemstones (hardness below 7) require more diligent care, including avoiding harsh chemicals, ultrasonic cleaners, and abrasive materials. These gems are best suited for pendants or earrings, minimizing exposure to impacts and friction.
Historical and Cultural Significance
While the Mohs scale provides a scientific measure of durability, the historical and cultural significance of birthstones adds another layer of meaning. Diamonds, for example, have been revered for centuries as symbols of invincibility and eternal love. Rubies have been associated with passion and courage, while sapphires represent wisdom and loyalty. These associations, combined with the gemstone’s physical properties, contribute to its enduring appeal.
Conclusion
The Mohs Hardness Scale is an essential tool for understanding the durability of birthstones and making informed choices when selecting jewelry. By considering the hardness of a gemstone, individuals can ensure that their cherished pieces will withstand the test of time and continue to sparkle for generations. While personal preference and aesthetic appeal are important factors, prioritizing durability ensures that a birthstone remains a beautiful and meaningful symbol for years to come.