Discovering Gemstones - December Edition
Turquoise, the traditional birthstone for the month of December, is a treasured gemstone dating back thousands of years. Very few minerals have a colour that is so well known that the name of the mineral becomes part of common language. Only three other mineral names - gold, silver and copper - are used more commonly than turqouise.
Climate is an important factor that determines where turqouise can grow. For that reason, it is found in few places on earth: dry and barren regions where acidic, copper-rich groundwater seeps downwards through soil and rock dissolving small amounts of copper. When this water is later evaporated, the copper combines with aluminum and phosphorus to deposit tiny amounts of turquoise on the walls of underground fractures. It is the copper that colours the turquoise, creating some of the most vivid blues and greens in gems.
Turquoise can also replace the rock in contact with these waters. If the replacement is complete, a chunk of turquoise will be formed. When the replacement is less complete, a spiderweb of veins can appear in the turquoise called matrix: evidence of the surrounding rock.
The legacy of turquoise adoration spans the globe. Isolated from one another, ancient people from Africa, Asia, South America and North America independently used turquoise as one of their preferred materials for producing gemstones, inlay and small sculptures.
In Iranian architecture, blue turquoise was used to cover the domes of palaces because it was seen as a symbol of heaven on earth. But perhaps the oldest use turquoise is by Ancient Egyptians stretching back as far as the First Dynasty. The most well-known pieces incorporating the gem are those recovered from Tutankhamun’s tomb, most notably the Pharaoh’s iconic burial mask which was liberally inlaid with turquoise.
Rough turquoise and turquoise objects were also held in high regard by Native Americans and were traded widely. This spread North American turquoise across the southwest and into South America. These early Native American jewelry designs were simple, and the turquoise was not set in metal findings.
Look A-Like Materials
Howlite and magnesite are light grey to white minerals that can have markings that resemble the spider webbing seen in turquoise. They can be dyed a blue colour that makes them look very similar to natural turquoise, however the dye does not penetrate deeply and scratching the back of the stone will often reveal the white interior. These dyed stones fooled many people when they first entered the marketplace and have had lasting damage on the market for genuine turquoise.
