Spinel – a gemstone in many colors
The earliest known spinel in gemstone quality dates back to 100 BC. It was found in a Buddhist tomb near Kabul, Afghanistan.
The name spinel probably comes from the Latin “spinella”, which means “little thorn”. The term refers to the pointed crystals of spinel, which resemble thorns.
Spinel comes in many different colors: in addition to red spinel and blue spinel, there are also green, pink and purple varieties. The colors are caused by elements such as iron (violet spinel, green-blue spinel) and chromium (green and cobalt blue). Other color-causing elements include zinc, manganese, cobalt and copper.
Spinel stone often mistaken for other stones
Throughout history, spinels have often been confused with rubies and sapphires.
Mines in Central and Southeast Asia yielded large spinel crystals known as balas rubies, which became prized possessions of emperors and kings.
The “Timur Ruby” and “Black Prince's Ruby” in the British Crown Jewels are also actually spinels.
Around 1600, the botanist, chemist and mineralogist Anselmus de Boodt compared the red of the ruby with that of the spinel. He found that the red of the spinel is less intense.
It is not only rubies that can be mistaken for spinels. At first glance, the many colors of this precious stone also make it look similar to other stones such as amethyst, aquamarine, emerald, tanzanite, sapphire or tourmaline.
The difference between spinel and other stones lies in their structure.
Like ruby and sapphire, spinel is also an oxide.
However, it differs from other stones in its octahedral crystal structure and simple light refraction. In addition, with a Mohs hardness of 7.5 to 8, it is also softer than ruby or sapphire, which have a Mohs hardness of 9.
The simple light refraction means that it only radiates one color in all directions. In the trade, stones like this are referred to as isotropic. In addition to isotropic crystals, there are also uniaxial and biaxial crystals. Stones with multiple axes also have multiple hues. Sapphire, for example, is a uniaxial stone and therefore displays two colors. Biaxial stones like tourmaline have three colors. These colors are not always clearly visible.
Influence of color on value
Bright red is the most sought-after and most valuable color of spinel gemstones, followed by cobalt blue, bright pink and bright orange. Pale colors such as lavender are often more affordable.
Origin and mining sites of spinel
This gemstone is found in metamorphic and igneous rocks such as gneiss, marble and basalt.
It is mined worldwide, including in Myanmar, Tanzania (Manghengi) and Sri Lanka. Spinels also come from Madagascar, Pakistan, Australia, Tajikistan, Afghanistan and Europe.
Use
Spinel is suitable for processing into jewelry due to its Mohs hardness of 7.5 to 8.
You can have gemstones from IGNEOUS set by a goldsmith in a unique piece of jewelry. Whether it is a bracelet, a necklace or a ring depends entirely on you.
Like the peridot, the spinel is also the birthstone of the month of August. If you are looking for a suitable jewelry gift for someone born in August, you should consider the stone. Among the many colors of this gemstone, there is bound to be the favorite color of the birthday child.
Inclusions and treatment
Spinels sometimes come in very pure form. Some have inclusions of apatite and healing cracks. Some spinels have fine rutile needles, which - similar to the star sapphire - can form a six-pointed star. This effect is visible in stones with the smooth cabochon cut.
Spinels are not heat-treated, as heating only causes a short-term change in hue. Treatments with oil, on the other hand, are more common to improve the clarity of the stones.
Most common cuts
Spinels are often cut in a cushion shape. They can also be found with a round or oval brilliant cut, with an emerald cut and also as a smoothly cut cabochon.
