In the month of December, the last month of the year, we have the birthstones tanzanite and zircon. Tanzanite was first discovered in the 20th discovery and had its name derived from its country of origin Tanzania, a state in Africa. The gemstone is known for its deep and saturated colours, often described as ‘velvety’, and comes in a range of rich blues and violets, with blue being the most valuable. It is also a gem for the 24th wedding anniversary.
The other December birthstone is Zircon, which caused some confusion as it is often mistaken for cubic zirconia due to similarities in the name and shared use as diamond simulants. However, cubic zirconias are lab created gemstones, whereas zircons are natural gemstones.
The name ‘zircon’ likely comes from the Persian word zargun, meaning ‘gold-coloured.’ Others trace it to the Arabic zarkun, meaning ‘vermillion.’ Given its wide range of colours—spanning red, orange, yellow, green, blue, and brown—both origins are plausible. Colourless zircon is known for its brilliance and flashes of multicoloured light, called fire, which resulted the gemstone to be mistaken for diamond in the past.
These two birthstones are quite similar to each other as they are both within the range of 6-7.5 in the Mohs scale of hardness. They can withstand normal light, heat and common chemicals, but will crack and erode when under stronger effects. As the two are mostly heat-treated in order to gain the desired colour variety, with blue being the most popular one, the gemstones may revert to their natural brownish hue when exposed to bright lights for long periods of time.
Tanzanite and Zircon are commonly worn as pendants and earrings, as they are not suited for daily wear, but they can be adorned as rings for special occasions provided the jewel has a protective mounting, like bezel setting as an example, and properly cared for. For cleaning, ultrasonic and steam cleaners are not recommended, so the safest way is by using a soft brush and mild soap in warm water. (Source: GIA; AGS)