Natural spinels are made from a hard magnesium aluminum oxide. Because they come in a wide variety of colours, these gemstones have been mistaken for rubies, sapphires, emeralds and other semi-precious stones. Unlike sapphires, rubies, and other stones, however, these gems have an octahedral crystal structure with a single refraction.
Where are natural spinels found?
The majority of spinel gemstones are found in Sri Lanka and Myanmar. However, these gemstones have also been found in Kenya, Madagascar, Cambodia, Thailand, and Vietnam.
What are synthetic spinels?
Synthetic spinels were first created by accident in the mid-18th century, though they were not regularly produced until the mid-2000s. Since then, transparent spinels have been produced in large sheets and in a variety of shapes. Although they have a glass-like appearance, lab-produced spinels can resist pressure better than glass can.
What is a red spinel?
Red spinels are a variety of spinel stones that have a deep, vibrant red colour. For most of history, there was no distinction made between red spinels and rubies. In fact, many famous gemstones that were thought to be rubies are actually red spinel. Some famous examples include:
- The Black Prince's Ruby: This 170-carat gem, which was acquired by Edward, Prince of Wales in 1396, is a red spinel that was once thought to be a ruby.
- Samarian spinel: This 500-carat ruby spinel is part of the Iranian Crown Jewels.
- The Mogul Names Necklace: This historic piece of jewelry has 11 spinel gemstones that have a total weight of more than 1,100 carats.
What colours do natural spinels come in?
There are many varieties of spinel gemstones.
- Almandine: These gems have a purple or violet colour. They can appear similar to amethyst.
- Balas ruby: This variety of the gem is known for its pink to pale red colour. It is also called a pink spinel. They often resemble pink topaz, morganite, and pink tourmaline.
- Blue spinel: This variety is light to dark blue in colour. These gems may resemble sapphires, topaz, or zircon.
- Flame spinel: The colour of this variety is orange to orange red, giving it its name.
- Gahnospinel: These gems are green to greenish black in colour due to the amount of zinc in them.
- Picotite: These gems are brown in colour because of the high amounts of chromium and iron within them.
- Pleonast: These gems range in colour from dark blue to green to black. They are often opaque.
- Rubicelle: They range in colour from yellow to orange.
- Ruby spinels: These gems have a red colour that are similar to rubies. They can also resemble garnets and tourmaline gemstones depending on the red hue.
What gemstones change colour?
Star spinels are a colour change stone similar to alexandrite. The colour of these gemstones depend on the light quality. colour change spinels are often small in size and shape.
- Daylight: During the day, most of the stones have a greyish blue colour.
- Incandescent light: The colour changes to amethystine in this type of light.