Weekly Obsession: December's Blue Hues

Weekly Obsession: December's Blue Hues

By Elsa Navarrete

December birthdays have claim to three gemstones; Zircon, Tanzanite and Turquoise. Each of these gemstones carries a unique blue tone.
Zircon (not to be confused with Zirconia) can be found in a variety of colours, but blue is the overwhelming favourite.


However, let's start with turquoise and its fascinating history and background. Turquoise is found in only a few places on earth: dry and barren regions where acidic, copper-rich groundwater seeps downward and reacts with minerals that contain phosphorus and aluminium. The colour is, of course, turquoise, but this colour actually varies from very green blue to light sky blue shades. The most-prized turquoise colour is an even, intense, medium blue, but some people prefer a greenish blue. Where the turquoise forms can create matrix, some dark brown, some tan, these resemble splotches or veins. Some people actually prefer the presence of matrix. The most expensive and preferred turquoise is with no matrix, the second is known as spiderweb turquoise, thin, delicate, web-like patterns across the face of the gemstone.

A sacred stone for the North American Indians, as well as, the Tibetans, it is often used by shamans in rituals and ceremonies. Turquoise is among the oldest known gemstones- it has been mined since 3,200 BC. It graced the necks of Egyptian Pharaohs and adorned the ceremonial dress of early Native Americans. It is said to promote mental and spiritual clarity and expansion to enhance wisdom, trust, kindness, understanding and even good luck.

Special care is required for turquoise regardless of whether or not it is enhanced. A porous gemstone, turquoise can absorb anything it touches. Avoid contact with cosmetics, perfumes, skin oil, acids, and other chemicals. Avoid dehydrating it or exposing it to heat.


Tanzanite may be a relative newcomer to the world of coloured stones, but it was one of the most exciting gem discoveries of the 20th century. Blue stones emerging from Tanzania were identified as the mineral zoisite in 1962. Not until 1967, though, did prospectors locate the primary source for this December birthstone: the Merelani Hills. It was eventually named tanzanite in honour of its country of origin. Tanzanite is often described as “velvety”, mostly because of its deep and saturated colour, which ranges from a pure rich blue to violet, with the blue considered most valuable.

Tiffany & Co. believed that tanzanite had international appeal and became its main distributor. In 1968, Tiffany launched a major advertising campaign to promote it. With its vivid colours, high clarity and potential for large cut stones, tanzanite quickly became a sensation. Today, it is not only a December birthstone, but it is also the gem for the 24th wedding anniversary.


The origins of the word “zircon” have elicited colourful debate. Some scholars believe it comes from the Arabic word zarkun, meaning “cinnabar” or “vermilion”. Others think the source is the Persian word zargun, or “gold colored”. Considering the broad colour palette for this December birthstone – red, orange, yellow, brown, green and blue – either derivation seems possible. Colourless zircon is known for its brilliance and flashes of multicoloured light, called fire, which have resulted in centuries of confusion with diamond.

During the Middle Ages, this December birthstone was thought to lull one into a deep sleep and scare off evil spirits. In the Hindu religion, zircon alternates with hessonite garnet as one of the nine gems of the navaratna. When worn together, the nine gems protect the wearer and bring wealth, wisdom and good health.

Victorians had a fondness for blue zircon. Fine specimens can be found in antique English jewellery from the 1880s.

To learn more visit the GIA Encyclopedia

Turquoise and Tanzanite pieces in the Covett Vault