Among the twelve birthstones associated with the months of the year, some stand out not only for their beauty and symbolism but also for their rarity and exorbitant value. While all birthstones carry a unique allure, a few command prices that place them in a league of their own. This article explores the most expensive birthstone—Alexandrite—and the close contenders, particularly Diamond, which has long been considered the pinnacle of gemstone value. Drawing from multiple authoritative sources, we will delve into the historical, geological, and cultural significance of these gems, as well as the factors that contribute to their staggering prices.
History and Lore
The most expensive birthstone, Alexandrite, is often cited as the rarest and most valuable of all. Its origins are steeped in both scientific discovery and historical legend. Discovered in 1830 in the Ural Mountains of Russia, Alexandrite was named after Czar Alexander II, who was the heir to the Russian throne at the time. The discovery of this gemstone on his birthday is the reason it received its regal name. The stone’s colors—bluish-green in daylight and purplish-red under incandescent light—align with Russia’s military colors, further cementing its status as the national stone of the country.
Alexandrite's color-changing property is unique and has fascinated gemologists and jewelers alike. This phenomenon, known as the Alexandrite effect, is due to the way the gemstone absorbs and reflects light. In natural daylight, it appears greenish, while in incandescent light, it appears reddish. This dual-color display has led to the stone being dubbed an “emerald by day and a ruby by night.” The rarity of this effect, combined with the scarcity of the stone itself, contributes to its high value.
Diamonds, on the other hand, have a more widely known historical significance. Known as the birthstone for April, diamonds have been revered for centuries for their hardness and brilliance. Ancient civilizations, including those in India and Egypt, were among the first to use and trade diamonds. Over time, diamonds became symbols of power and wealth, particularly during the European Renaissance. By the 20th century, diamonds had also become synonymous with eternal love, largely due to aggressive marketing campaigns by diamond companies. Today, diamonds remain one of the most sought-after gemstones in the world.
Geological Formation and Sources
The value of a gemstone is often directly related to its rarity, color, clarity, and the difficulty of its extraction. In the case of Alexandrite, these factors all play a role in its status as the most expensive birthstone.
Alexandrite is a variety of chrysoberyl, a mineral that forms in metamorphic and igneous rock environments. The presence of chromium and vanadium in the mineral structure is what gives Alexandrite its color-changing properties. It is typically found in granite pegmatites and mica schists, where it forms under high pressure and temperature conditions. The Ural Mountains remain one of the primary sources of Alexandrite, but high-quality specimens are also found in Brazil, Madagascar, and Sri Lanka.
Due to its rarity, Alexandrite is not mined in large quantities. High-quality Alexandrite, especially stones that display the full color change effect, is extremely scarce. This scarcity, combined with the difficulty of cutting and setting such a sensitive stone, makes Alexandrite one of the most valuable birthstones on the market.
Diamonds, by contrast, are formed deep within the Earth’s mantle, approximately 140 to 190 miles below the surface, under extreme pressure and high temperatures. The carbon atoms in the mantle crystallize into diamonds over millions of years. These diamonds are brought to the surface through kimberlite or lamproite volcanic eruptions. The most significant diamond sources in the world include Africa (particularly South Africa, Botswana, and Angola), Russia, Australia, and Canada.
Despite their abundance, diamonds that are of high quality—particularly those that are colorless, large, and internally flawless—are extremely rare. These diamonds are categorized as Type IIa, which means they contain no nitrogen or boron impurities and are the purest form of carbon. Such stones are the most valuable and can command prices of $3,000 to $10,000 per carat, depending on their weight, color, and clarity.
Gemological Properties
Understanding the scientific properties of a gemstone is essential in determining its value and appeal. The following table summarizes the key gemological properties of Alexandrite and Diamond, highlighting why they are among the most expensive birthstones:
| Property | Alexandrite | Diamond |
|---|---|---|
| Chemical Formula | BeAl₂O₄ | C (Carbon) |
| Hardness (Mohs Scale) | 8.5 | 10 |
| Refractive Index | 1.74–1.76 | 2.417 |
| Color | Bluish-green to purplish-red (color change) | Colorless to fancy colors (red, blue, green, etc.) |
| Transparency | Transparent to translucent | Transparent |
| Luster | Vitreous | Adamantine |
| Crystal System | Orthorhombic | Isometric (cubic) |
| Density | 3.71–3.78 g/cm³ | 3.52 g/cm³ |
| Special Properties | Color change effect | Color change in fancy color diamonds |
As seen in the table above, Alexandrite’s unique color change effect is a distinguishing feature that sets it apart from other gemstones. This property is due to the way the gemstone absorbs and reflects different wavelengths of light, depending on the light source. While other gemstones can exhibit color changes under different lighting, the clarity and dramatic shift in Alexandrite is unmatched.
Diamonds, in contrast, are uniquely hard and have the highest refractive index of any natural gemstone. This gives them their characteristic brilliance and fire. The hardness of 10 on the Mohs scale means that diamonds are not easily scratched, making them ideal for everyday wear in jewelry.
Symbolism and Metaphysical Beliefs
Both Alexandrite and Diamond carry deep symbolic meanings, which have contributed to their enduring popularity and value.
Alexandrite is often associated with transformation and adaptability due to its color-changing properties. In some cultures, it is believed to bring protection, good luck, and emotional balance. Alexandrite is also thought to enhance mental clarity and intuition, making it a popular choice for those seeking spiritual growth or emotional healing. In the realm of metaphysical beliefs, Alexandrite is said to harmonize the heart and solar plexus chakras, promoting a sense of well-being and confidence.
Diamonds, as the birthstone of April, have long been associated with strength, invincibility, and eternal love. In ancient times, diamonds were believed to be gifts from the gods, imbued with divine power. The Greeks and Romans considered diamonds to be symbols of immortality, while in India, they were used in religious rituals and believed to possess spiritual power. In modern times, diamonds are most commonly associated with marriage and commitment, thanks to the marketing strategies of the 20th century.
Fancy color diamonds, such as pink, blue, and red diamonds, are also believed to carry special energies. For example, pink diamonds are said to bring compassion and empathy, while blue diamonds are associated with serenity and wisdom. These beliefs, while not scientifically proven, have contributed to the cultural and emotional value of diamonds.
Care and Cleaning
Due to their high value and delicate nature, both Alexandrite and Diamond require special care to maintain their appearance and longevity.
Alexandrite should be cleaned using mild soap and warm water. Ultrasonic and steam cleaners are generally not recommended because the intense vibrations or heat can potentially damage the stone or its setting. It is also important to avoid exposing Alexandrite to extreme temperatures or harsh chemicals, as this can affect its color and clarity. When not in use, Alexandrite should be stored in a soft cloth or jewelry box to prevent scratches.
Diamonds, being the hardest natural substance on Earth, are more durable and can be cleaned using a mild detergent and warm water. They can also be cleaned using ultrasonic or steam cleaners, provided the setting is secure and the stone is not loose. However, diamonds with fancy color treatments (such as irradiation or high-pressure, high-temperature (HPHT) treatments) should be handled with care, as these treatments can be sensitive to heat and chemicals.
Regardless of the gemstone, it is always advisable to have jewelry professionally cleaned and inspected by a qualified jeweler, especially if it contains rare or valuable stones like Alexandrite or high-quality diamonds.
Conclusion
In the world of birthstones, Alexandrite stands out as the most expensive gemstone, with prices ranging from $15,000 to $70,000 per carat for high-quality specimens. Its unique color-changing properties, scarcity, and historical significance all contribute to its exceptional value. While Diamonds are often considered the most valuable gemstone in general, in the context of birthstones, Alexandrite’s rarity and distinctive features place it at the top.
Understanding the geological, historical, and symbolic aspects of these gemstones helps explain their premium pricing and enduring appeal. Whether for jewelry, investment, or personal significance, the most expensive birthstones continue to captivate gemstone enthusiasts and collectors alike.