45th Wedding Anniversary Gift
Sapphire. A member of the corundum family. The red variety is called Ruby and all other colours are Sapphire, their name prefixed by their colour e.g. yellow sapphire, green sapphire etc. Sapphire alone without a colour prefix is assumed to be blue.
Very occasionally, naturally occurring colour-change sapphires are found, going from blue in daylight to purple under incandescent light, not to be confused with the man-made colour change sapphires that are there to imitate the very rare Alexandrite gemstone.
Sapphire is a very durable material. It is highly scratch resistant, bearing a score of 9 on Moh’s scale of hardness. This hardness makes sapphire particularly suitable for all types of jewellery. It should aways be remembered that when hardness of a gemstone is quoted, it refers to the gem materials resistance to scratches, it can, however, still be chipped if given a sharp knock.
Synthetic sapphire (grown by man in a laboratory) is used on many quality watches as the ‘glass’. It is also used in supermarket scanners!
Natural sapphire is found in many locations around the world. Montana in the USA, Sri Lanka, Africa, and Australia. Kashmir in the Himalayas in North West India was a source of good, blue colour sapphires but this mine is now exhausted.
The sapphires mined in Montana come in all colours, however, those from the Yogo Gulch area tend to be of a very uniform ‘cornflower blue’ colour and do not tend to undergo the heat treatment to improve colour that occurs with many coloured gemstones. The sapphires from the Yugo Gulch area occur in vertical, igneous dikes (dykes), which formed when magma filled a fracture in a near vertical position. The sapphires found there tend to be flattened crystals and not particularly large in size.
The original stones were discovered accidentally during the gold rush when a gold prospector called Jake Hoover found blue pebbles as he was panning for gold. He sent a box of these blue stones to Tiffany & Co who reported back to him that they were sapphires and purchased them from him. After that, Hoover and his partners concentrated on the sapphires rather than the meagre amount of gold they had found in the area. Over the years, the area was mined commercially although today after many changes of ownership, it is fairly idle with just a few miners bringing gems to the surface by hand.
Over time it was often said that sapphires from Sri Lanka were pale blue and those from Australia were very dark, but, in reality, you will find pale and dark gems from both locations. The origin of a gem can only be assessed by a reputable gem laboratory. who will need to carry out many tests and investigations to ascertain where it was likely to have been mined.
Some sapphires can show an effect called “asterism” which is when the inclusions in the sapphire form in such as way that they intersect each other at 60° angles; when the stone is cut “en-cabochon”, with a flat base and a domed top, you can see a six-rayed star. It can be seen when white light reflects off the surface of the inclusions through the curved surface of the stone.
Sapphire is traditionally thought of as a blue gemstone, in shades from very pale blue to almost black. However, it can be found in all colours of the rainbow (except red when it is designated as Ruby). Corundum, the family to which Ruby and sapphire belong, in its pure form, is colourless aluminium oxide. It contains various trace elements which are responsible for the final colour of the gemstone. The fact that Sapphire is found in so many colours means that it lends itself beautifully to being made into single colour and mulitcolour gem set items such as pendants, bracelets, rings and earrings.
As with all gemstones, we would recommend any sapphire jewellery be removed before undertaking any type of hard work to protect the gems.
We can make a sapphire item to your specifications, however, please be aware that this can be a lengthy process so don’t leave it to the last minute if it is for a special occasion as the gem has to be sourced and often the mount will have to be handmade by our jeweller, a highly skilled craftsman who will work on the item for hours at a time. We are always pleased to be able to obtain a quote for a bespoke item.
Ruby is from the same Corundum family as sapphire. Read more about Ruby on this post:
