December is unique in that it is associated with multiple birthstones, each offering a very different combination of history, physical properties, and visual appeal. Tanzanite, zircon, and blue topaz were added over time to provide alternatives to turquoise, giving December-born individuals a wider range of choices based on durability, color, and personal preference.
Tanzanite: Rare by Nature
Tanzanite is the newest and rarest of December’s birthstones. It was discovered in 1967 in northern Tanzania and is found in only one location worldwide. This geographic limitation makes tanzanite inherently finite—once existing deposits are exhausted, no new sources are expected.
Tanzanite is known for its striking blue-to-violet coloration and pleochroism, meaning it can show different colors depending on the viewing angle. Most tanzanite on the market is heat-treated to enhance its blue tones, a stable and accepted practice in the gemstone industry.
With a Mohs hardness of 6 to 6.5, tanzanite is softer than sapphire or diamond, making it better suited for earrings, pendants, and occasion-wear rings rather than daily-use jewelry.
Historically, tanzanite lacks the ancient legacy of other gemstones, but its rarity and limited supply have made it increasingly significant in modern fine jewelry.
Zircon: One of Earth’s Oldest Gemstones
Zircon is often misunderstood or confused with cubic zirconia, but the two are entirely different. Natural zircon is one of the oldest minerals on Earth, with some crystals dating back over 4 billion years.
Blue zircon became associated with December due to its brilliance and fire—qualities that rival diamonds. Its high refractive index gives it exceptional sparkle, often surprising those unfamiliar with the stone.
Zircon ranks 6 to 7.5 on the Mohs scale, depending on treatment and structure. While durable enough for many types of jewelry, it should be worn with care to avoid abrasion.
Historically, zircon was used in ancient India and the Middle East, where it was believed to promote rest, prosperity, and wisdom. Today, it is valued for its optical performance and classic gemstone appeal.
Blue Topaz: Durable and Accessible
Blue topaz is the most commonly recognized December birthstone in modern jewelry. While natural blue topaz is rare, most blue topaz on the market is created by treating colorless topaz with heat and irradiation—an industry-standard process that produces stable, long-lasting color.
Blue topaz is popular due to its:
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High clarity
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Consistent color
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Affordability
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Excellent durability
With a Mohs hardness of 8, blue topaz is well-suited for everyday jewelry, including rings, bracelets, and pendants. Its clean, crisp blue appearance ranges from light sky blue to deeper London blue tones.
Though blue topaz does not have the ancient ceremonial history of turquoise or zircon, its practicality and visual clarity have made it a staple in contemporary birthstone jewelry.
Comparing December’s Birthstones
Each December birthstone offers a distinct advantage:
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Tanzanite: Rare, vivid, and modern
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Zircon: Brilliant, historic, and naturally fiery
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Blue Topaz: Durable, affordable, and versatile
The right choice depends on how the jewelry will be worn, desired longevity, and aesthetic preference.
December Birthstone Jewelry at Johnston Jewelers
At Johnston Jewelers, we help clients navigate these differences with clarity and honesty. Whether selecting a birthstone gift or designing a custom piece, understanding each stone’s properties ensures the jewelry fits both lifestyle and expectations.
With over 53 years of experience, Johnston Jewelers offers December birthstone jewelry that balances beauty, durability, and thoughtful design—allowing each gemstone to be appreciated for what it truly is.