What is a Star Sapphire?
Star sapphires are a sub-category of sapphires that display unique asterism. Asterism is a kind of optical effect that can occur in gemstones that has a very unique and appealing aesthetic. Asterism occurs when miniscule needles of crystal silk existing within the sapphire reflect light, forming a star shape. Most typically, star sapphires have six points to them, though stars with more and fewer points to them do also exist. This asterism is a beautiful feature in the gemstone that makes it highly sought after.
Some of the largest sapphires in the world are star sapphires, and their design evokes connections to nature that are highly appealing. The connection to nature is attained by the fact that the stone retains so many of the sapphire’s natural characteristics. Star sapphires are closer to the raw sapphire gemstone than many other varieties of sapphire.
The Perfect Star Sapphire
While there are always going to be variations of certain patterns in gemstones, and there will always be an ideal for how the ‘perfect’ gemstone should look. With star sapphires, the ‘star’ itself should be perfectly centred within the stone. Each one of the points of the star should be equal in length, and the star design should be crisp and clearly divided from the colour of the stone. Stars can be found in sapphires of any colour, and there is no ideal colour for a star sapphire. This is perhaps another element of their popularity, as people are free to choose their preferred colour. There are even black star sapphires, occurring when the stone features hematite in large quantities.
Stars in sapphires should be a clear colour, allowing some transparency into the stone. This raises the issue of clarity. Establishing the ideal clarity of a star sapphire is complicated because of the need for transparent stars. The existence of the stars themselves guarantees that there will always be inclusions to some degree within the stone. Therefore, the ideal star sapphire has as much transparency as it can whilst still allowing for the star to be clear and well-defined.