December Birthstone: Tanzanite
In the world of gemstones, December birthstone wearers are spoilt for choice with four stunning options: tanzanite, turquoise, blue iolite, and blue sapphire. Let's delve into the properties, care, and key differences of these gems to help guide your selection.
Tanzanite
Tanzanite, a blue-purple hued gemstone discovered in Tanzania in 1967, is a variety of zoisite that boasts a hardness of 6.5 on the Mohs scale. Its most distinctive feature is its pleochroism, which means the colour shifts from purple to blue depending on the viewing angle.
Care for tanzanite requires avoiding heat, sudden temperature changes, strong knocks, and storing it separately to prevent scratches. This gemstone is softer than sapphire and less durable for everyday wear, but it is generally more affordable than blue sapphire with similar quality. Tanzanite's unique violet-blue colour sets it apart, making it a prized choice among gemstone enthusiasts.
Turquoise
Turquoise, with its opaque blue to greenish blue hues, has a hardness of 5-6. Its colour is derived from copper (blue) and iron/chrome (green). This gemstone is relatively soft and often stabilized or treated for durability.
Turquoise requires careful handling due to its porosity and sensitivity. It should be protected from chemicals, perfumes, oils, prolonged exposure to sunlight, and water. Its distinctive opaque look sets it apart from transparent blue stones, and it is popular for its unique colour and cultural significance.
Blue Iolite
Blue iolite, with its transparent blue-violet hue and hardness of ~7-7.5, is pleochroic, showing different shades (blue to violet to gray) depending on the viewing angle. Despite offering interesting colour shifts, it is sometimes confused with tanzanite and spinel, and it is less brilliant than sapphire and tanzanite.
Care for blue iolite involves avoiding harsh chemicals and ultrasonic cleaners, and storing it separately to prevent scratching. It serves as a good mid-range option for those seeking a gemstone with colour shifts without the brilliance of sapphire or tanzanite.
Blue Sapphire
Blue sapphire, with its transparent deep blue to violet-blue hue and hardness of 9 (Mohs scale), is among the hardest and most durable blue gems. It is found worldwide and prized for its brilliance, durability, and range of blue hues.
Blue sapphire is suitable for everyday wear, and it can be cleaned with warm soapy water or ultrasonic cleaners. It is generally more expensive than tanzanite or iolite for top quality, but it is among the most valuable and sought-after blue birthstones.
Summary
- Durability: Blue sapphire (hardness 9) is the most durable, ideal for daily wear. Tanzanite (6-7) and turquoise (5-6) are softer and require more careful handling. Iolite is intermediate (~7-7.5).
- Color & Rarity: Tanzanite is rarer and has a striking violet-blue color unique to Tanzania. Turquoise is opaque and distinctive with copper-derived blue-green hues. Blue sapphire is prized for vivid, saturated blues and superior brilliance. Iolite offers pleochroism but less brilliance than sapphire or tanzanite.
- Care: Turquoise needs the most careful care due to porosity and sensitivity; tanzanite should be protected from heat and harsh knocks; sapphire is very durable and easier to maintain; iolite requires gentle cleaning.
- Value: Generally, sapphire is the most valuable and expensive blue birthstone, with tanzanite next, turquoise and iolite usually more affordable but with niche appeal.
This comparison can help guide choices depending on preferences for color, durability, and care requirements among December birthstones.
Tanzanite has a prismatic shape with a rectangular cross-section and can have striations running parallel to the length of the crystal.
Tanzanite is often heat treated to enhance the desired purplish-blue colour.
High quality tanzanite can be a saturated violet-blue, reminiscent of a fine sapphire, or a more unusual, predominantly violet color.
Heating tanzanite eliminates the yellow, leaving a dichroic gemstone displaying blue and violet.
The color appearance of tanzanite can vary depending on the cutter's choice of fashioning the stone.
Tanzanite can be transparent to translucent with varying colour saturation.
Tanzanite was first brought to the Western fine jewellery market by Campbell Bridges.
Tanzanite displays trichroic pleochroism, showing three different colors: blue, yellow, and pinkish purple.
Tanzania is the only known source of tanzanite.
- In addition to their gemmological characteristics, December birthstone wearers may also be interested in the various courses, workshops, and publications offered by foundation organizations dedicated to the Study of gemstones, as these could enhance their knowledge about tanzanite, turquoise, blue iolite, and blue sapphire.
- For those seeking a unique piece of fashion-and-beauty jewelry, a membership to select public auction houses could provide the opportunity to bid on rare, high-quality tanzanite, turquoise, or blue sapphire gemstones, adding a touch of luxury to their lifestyle.
- Home-and-garden enthusiasts might appreciate the cultivation of specific plants, such as the ch loansia tanzanica, a beautiful flower native to Tanzania, which complements the stunning deep blue hues of tanzanite.
- Moreover, the fashion and beauty industry could capitalize on the exclusive nature of these gemstones, creating limited-edition accessories like designer jewelry and cosmetic products infused with ground turquoise or tanzanite, offering customers a unique fusion of gemmology and lifestyle.
