Red spinel has frequently been mistaken for ruby. While modern science now enables us to easily tell the difference between the two gemstones, this was not always the case. Centuries ago, upper class and royal individuals would use rubies to decorate their robes, ornaments and accessories. However, it has since been discovered that some gemstones thought to have been rubies are in fact red spinels. Perhaps the most well-known and most sought-after spinel colour is the rich red spinel. However, these gemstones can also be found in a range of hues including orange, pink, purple, and even blue – which are extremely rare. The different colours found in spinels are due to the traces and amounts of cobalt, iron and chromium whose presence determines the colour. In most cases spinel gemstones are more reflective and have a glittery appearance compared to rubies. Spinels also feature octahedral crystal forms (whereas rubies are more like hexagonal prisms). Ranging from a 7.5 to 8 on the Mohs hardness scale, spinels are relatively tough gemstones and with reasonable care can be worn daily. 

Spinel was recently added as an August birthstone, sharing this month with peridot. It can also be used to celebrate the 22nd wedding anniversary.