Spinel
Spinel
Synthetic spinel, was first produced accidentally during an attempt to make a satisfactory blue synthetic sapphire by the Verneuil process.
Synthetic spinel is widely used because it is slightly softer than synthetic corundum, it can be fashioned more rapidly and less expensively. Secondly, several of the colours in which it is made are better imitations for a number of natural stones than those made in synthetic corundum.
Spinel is a favourite of jewellers due to its brilliance, hardness and wide range of spectacular colours. Spinel and Corundum are chemically similar. Spinel is magnesium oxide and Corundum is aluminium oxide. They are similar in luster, density and hardness.
Spinel is 9/10 on the Mohs scale of hardness and heat resistant so ideal for wax setting.
Please note that synthetic Aquamarine and Blue Zircon are lab-grown spinel and are therefore not true synthetics, but rather classed as simulants.