Spinel is a gemstone that belongs to the oxide mineral family. It is chemically composed of magnesium aluminum oxide and is a hard, durable stone with a Mohs hardness of 8. Spinel can be found in various colours, including red, blue, pink, purple, brown, black, and colourless. It has a vitreous luster and is commonly faceted to showcase its brilliance.
Spinel has a rich history and has been known and prized as a gemstone for centuries. The ancient Egyptians used spinel in their jewelry, and it was also popular among the ancient Greeks and Romans. The name "spinel" is derived from the Latin word "spinella," meaning "little thorn," which refers to its pointed crystal formations. Spinel was often mistaken for other gemstones in the past, including ruby and sapphire. For example, the Black Prince's Ruby, a famous gemstone that is part of the British Crown Jewels, is actually a red spinel. Spinel has also been mistaken for diamond due to its high refractive index.
Spinel has a chemical formula of MgAl2O4 and a specific gravity of 3.5-4.1. It is usually found in octahedral or rounded crystal formations and has a conchoidal fracture. Spinel is a hard and durable stone, making it ideal for use in jewelry. It has a refractive index of 1.718.
Spinel can be found in a wide range of colours, including red, blue, pink, purple, brown, black, and colourless. The most common colour of spinel is red, which is often mistaken for ruby. Pink and blue spinel are also highly prized, and they can be found in various shades and hues. The colour of spinel is caused by the presence of different metal ions, such as chromium, iron, and cobalt. Cobalt spinel is a variety of spinel that is coloured by the presence of cobalt. It is a rare and highly valued gemstone due to its rich blue colour, which can range from light to dark shades.
Spinel is rarely treated, and it is generally sold as natural gemstone. However, some spinel may be heat-treated to enhance its colour or clarity. Oil in fissure as a treatment to improve its clarity resulting in a more desirable gemstone is slightly more common.
Spinel can be found in many locations around the world, including Sri Lanka, Myanmar, Tanzania, Vietnam, and Afghanistan. The most famous source of red spinel is the Mogok region of Myanmar, which produces some of the finest red and pink spinel in the world. Other notable sources of spinel include Vietnam and Tanzania, which are known for their cobalt blue and pink spinel, respectively.
Spinel can be produced synthetically in a laboratory by flux, flame fusion (melt) or hydrothermal, and it has been manufactured since the early 1900s. Synthetic spinel has almost the same properties as natural spinel, including its hardness, durability, and colour. Synthetic spinel is often used as a substitute for natural spinel in jewelry, and it is also used in industrial applications, such as in high-temperature ceramics and electronic components.
Spinel is a popular gemstone used in jewelry, and it is often used as a substitute for other gemstones, such as ruby and sapphire. It is especially popular for use in engagement rings, as it is a durable stone that can withstand daily wear. Spinel is also used in other forms of jewelry, such as earrings, necklaces, and bracelets.