Asterism, which is more commonly referred to as ‘the star effect’ is a marvellous phenomenon seen only in certain gemstones, with the most prized examples occurring in sapphires and rubies. The star is caused by fine needle-like inclusions, known as ‘silk’, that line up perfectly to reflect incoming light into a star pattern, commonly exhibiting four, six, or (rarely) twelve rays, radiating out from a central point.
As is the case with all coloured stones, the colour is paramount, and the most important quality factor. In addition to this, the most valued star stones display strong and straight white rays, with a centred star that floats smoothly across the surface with the right light source. Only superior cutting will release a gem’s beauty, with the finest star stones cut and polished as symmetrical and well-balanced cabochons.
Sri Lanka, formerly known as Ceylon, is often referred to as the jewel box of the Indian Ocean, and has produced some of the finest star gemstones in existence, including the Star of India Sapphire. With an incredible weight of 563.35 carats (around the size of a golf ball!), this gemstone has a celestial milky blue hue and remarkable asterism, which is perfectly centred and visible on both sides of the stone.
Commonly used as talismans to protect against the evil eye, the Sinhalese used star sapphires to ward off witchcraft of all kinds. To others, the crossing of three bands of light represented hope, faith and destiny, and it was believed that these gems would protect travellers from ill health. Flemish mineralogist, Anselmus de Boodt, wrote in 1609 that the Germans revered star sapphires as a siegsten, “victory stone”, and they are still occasionally referred to as this today.
No two stars are the same, with the asteria being as unique as the growth characteristics of the gem itself. Each star has its own personality in appearance and movement, which makes matching pairs all the more rare and highly valuable! At Berganza, we have an exquisite collection of star sapphires and rubies, including impressive dress rings certain to turn heads, as well as earrings and cufflinks that elegantly reflect the light.
Our jewellery specialists would be delighted to welcome you to the Berganza showroom to assist you in your search for the new star of your jewellery collection!