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.
