Gemstones that change colour are some of the most phenomenal and rarest types to exist.
People have been fascinated by gemstones for millennia, but some discoveries made in the past century have led to the revelation of a few properties in their structure that are responsible for causing captivating optical effects. Different types of gemstones exhibit several optical effects, but in recent years the fascinating phenomenon of changing colours has gained immense popularity. Here are five gemstones that change colour and find out what is the cause behind this phenomenon.
Alexandrite
Gem enthusiasts use the catchphrase "Emerald by Day and Ruby by Night" to refer to Alexandrite's strange ability to change colours in different lights. At first, mineralogists had believed the gemstone to be an emerald - until it turned purple-red when exposed to lamplight and startled them. The chemical composition of the gem enables this variety of Chrysoberyl its rare property due to the presence of chromium traces alongside titanium and iron, which causes Alexandrite to change its colour.
Sapphires
The most common and prized sapphire colour is royal blue which, despite being richly saturated, is still transparent. In fluorescent light or daylight, colour-changing sapphires will appear from a bright blue to violet-blue. When you put a sapphire under a lamp, it looks somewhat reddish-purple. The presence of metallic traces in the gemstone causes a shift in its colour that we often see.
Garnets
Colour-altering garnets exhibit the widest variety of shifts in colours. Some garnets alter colours from teal to rose pink, while others change from bronze to purplish pink and from grey to a purplish-pink. But this effect is limited only to Pyrope Garnets, and it is caused as a result of very high contents of vanadium - a metallic element.
Tourmaline
Tourmaline exhibits colour change and can produce a spectacular cat's eye effect. Apart from these two effects, recently, a geologist discovered that a Tourmaline collected from Tanzania exhibited another exceptional colour effect. This phenomenon, known as the Usambara Effect, causes the gemstone to shift colour dramatically from green to red when it attains a certain thickness.
Diaspore
During the 1970s, miners unearthed transparent, large crystals of diaspore in Turkey. This gemstone is naturally found in colours like green, yellow or earthy brown. It alters colour under fluorescent or natural light, appearing kiwi-green or light green with flashes of yellow. Under incandescent lighting, diaspores acquire more of a champagne colour. The colour-changing properties are caused as a result of manganese content.
Get yourself one of these phenomenal gemstones and flaunt its bedazzling colour-changing properties.
