Birthstone jewelry carries a deep personal significance, representing the month of an individual’s birth and believed to bestow good fortune upon the wearer. Each month is linked to a specific gemstone, and their value varies considerably. This article will explore the most expensive and rarest of these birthstones – diamond, ruby, and alexandrite – delving into their history, gemological properties, and the factors contributing to their high price.
History and Lore
The association of gemstones with specific months dates back centuries, though the modern birthstone list is a relatively recent standardization. Historically, gemstones were valued for their beauty, rarity, and perceived mystical properties. Diamonds, rubies, and emeralds have consistently held positions of esteem throughout history, often adorning royalty and symbolizing power and status.
Diamonds, particularly, have a long and storied past. Their exceptional hardness and brilliance led to their early use as symbols of invincibility and eternal love. Rubies, with their vibrant red hue, were associated with passion, vitality, and protection in ancient cultures. Alexandrite, discovered more recently in the 19th century, quickly gained prominence due to its unique color-changing ability, becoming the national stone of Russia and linked to the country’s military colors.
Geological Formation and Sources
Diamonds are formed deep within the Earth’s mantle under immense pressure and heat. They are brought to the surface through volcanic eruptions, often found in kimberlite pipes. Historically, significant diamond sources included India, but today, major mining operations are located in countries like Russia, Botswana, and Canada. The Argyle mine in Western Australia, a primary source of pink diamonds, closed in 2020, further exacerbating the scarcity of these coveted stones.
Rubies, members of the corundum family, form in metamorphic rocks. The most prized rubies originate from Myanmar (Burma), though they are also found in Thailand, Sri Lanka, and Africa. The specific geological conditions required for ruby formation contribute to their relative rarity.
Alexandrite, a variety of the mineral chrysoberyl, was first discovered in the Ural Mountains of Russia in the 1830s, reportedly on the birthday of Czar Alexander II, hence its name. Today, alexandrite is also found in Brazil, Sri Lanka, and East Africa, but the Russian stones are considered particularly valuable.
Gemological Properties
Diamonds are renowned for their exceptional hardness, registering a 10 on the Mohs scale, making them the hardest naturally occurring substance on Earth. They are composed of pure carbon and are typically colorless, though they can occur in various fancy colors, including pink, blue, and yellow. Their brilliance and sparkle are due to their high refractive index. Diamonds are evaluated based on the “4Cs”: carat, cut, clarity, and color. The most valuable diamonds are colorless (D color), internally flawless, and of a significant carat weight.
Rubies, also scoring a 9 on the Mohs scale, are the hardest gemstone after diamonds. Their vibrant red color is caused by the presence of chromium. Fine rubies are transparent with minimal inclusions. The intensity and purity of the red hue are key factors in determining a ruby’s value.
Alexandrite possesses a unique property known as pleochroism, meaning it displays different colors when viewed from different angles. More notably, it exhibits a color-change effect, appearing bluish-green in daylight and purplish-red in incandescent light. This remarkable characteristic is due to the presence of chromium and iron within its crystal structure. Alexandrite typically ranges between 2.5 and 3 on the Mohs scale.
The following table summarizes the Mohs hardness scale for these three birthstones, alongside other relevant gems:
| Birthstone | Month | Mohs Scale |
|---|---|---|
| Diamond | April | 10 |
| Sapphire | September | 9 |
| Ruby | July | 9 |
| Topaz | November | 8 |
| Aquamarine | March | 7.5–8 |
| Pearl | June | 2.5–4.5 |
| Opal | October | 5.5–6.5 |
| Peridot | August | 6.5–7 |
| Garnet | January | 6.5–7.5 |
| Amethyst | February | 7 |
Symbolism and Metaphysical Beliefs
Throughout history, these gemstones have been imbued with symbolic meaning. Diamonds represent eternal love, strength, invincibility, and purity. Rubies symbolize passion, love, vitality, energy, courage, and protection. Alexandrite, due to its color-changing nature, is often associated with balance, transformation, and good fortune.
Market Value and Rarity
Currently, alexandrite is considered the most expensive birthstone, with prices ranging from $15,000 to $70,000 per carat. This high value is attributed to its extreme rarity and unique color-changing properties. Diamonds follow closely behind, valued between $3,500 and $10,000 per carat, with exceptional colorless diamonds commanding even higher prices. The closure of the Argyle mine has significantly increased the value of pink diamonds. Rubies are the third most expensive, ranging from $3,000 to $12,000 per carat, with the finest specimens rivaling the price of diamonds.
The rarity of these gemstones is a primary driver of their value. Diamonds, while relatively abundant in terms of total weight mined, are scarce in large, flawless qualities. Rubies of exceptional color and clarity are exceedingly rare. Alexandrite, with its limited sources and unique properties, is one of the rarest gemstones available.
Care and Cleaning
Due to their hardness, diamonds are relatively durable and can be cleaned with warm water, soap, and a soft brush. Rubies and sapphires, also quite durable, can be cleaned similarly. However, Alexandrite, being a softer stone, requires more careful handling. It should be cleaned with a soft cloth and mild soap, avoiding harsh chemicals or ultrasonic cleaners. It is best to have alexandrite jewelry professionally cleaned to avoid damage.
The 3 Rarest Birthstones
The three rarest gemstones among the twelve birthstones are diamond, ruby, and emerald. These precious stones are difficult to find, contributing to their higher price points. Alexandrite and Tanzanite are also considered rare.
Factors Influencing Gemstone Value
The cost of birthstones is determined by the “4Cs”: color, cut, clarity, and carat. Color refers to the hue, tone, and intensity of the gemstone. Rich, vibrant hues generally command higher prices, except for diamonds, where colorless stones are most valuable. Cut refers to the proportions, symmetry, and polish of the gemstone, impacting its brilliance and fire. Clarity refers to the absence of inclusions or blemishes. Carat refers to the weight of the gemstone, with larger stones generally being more valuable.
Conclusion
Diamond, ruby, and alexandrite represent the pinnacle of gemstone value and rarity. Their unique geological origins, exceptional gemological properties, and rich historical significance contribute to their enduring appeal. These stones are not merely beautiful adornments but symbols of enduring love, passion, and good fortune, making them highly sought-after treasures for generations to come.