Sapphire is classified as a precious gem or fundamental along with ruby, emerald and diamond.
Can be of different colors like orange, green, or yellow but the most valuable are severe or gentian blue blue. Some sapphires cabochon carved with the optical effect of a star inside.
- Hardness: 9 Mohs
- Specific Gravity: 3.9 to 4.1
- Conchoidal fracture
- Color: Blue, orange, green, etc.
- Vitreous luster, and occasionally it may seem silky
- Variable transparency, and possible presence of inclusions that give a milky appearance.
Sapphires producing countries.
First a clarification, because we have to differentiate between source and origin.
Country of origin means the mine and origin is where it is marketed and handled is. For example we can have a sapphire whose origin is a mine in Sri Lanka and its origin is Thailand because it is here that has been carved and sold.
Thailand is the country of marketing size and sapphires in the world, but just have a few small mines.
The main sites in the world are found in Madagascar where sapphires found exceptional quality. Sri Lanka also remains one of the main producers, having considered the highest quality for many years. So when we speak of a Ceylon (modern Sri Lanka) sapphire, sapphires we are talking about a magnificent color. Finally we found sites in Thailand, Australia, Cambodia, China and Vietnam.
Rate a sapphire
Sapphires are valued based on their color, clarity, cut and size.
- Color: Unlike the diamond, there is a color scale so there is a highly subjective thereon. In principle sapphires with intense blue but alive and transparency would be the most valuable color. A gray or green mixed with blue veil would decrease its value, and when mixed with blue violet it increases (color Ceylon).
As the degree of color intensifies the stone loses transparency, so we must seek an intermediate between the intense color and transparency. The light must pass enough but at the same time allow an intense color. Very dark blue (Australians) have a lower value.
To assess a sapphire is important whether the color is natural or is heat treated, and to what extent. Today most sapphires are treated at source.
- Purity: As for the purity say that the fewer inclusions (impurities) has and purer sapphire, will also be more valuable.
- Size: Sapphires generally come in oval or emerald cut. The cabochon cut (rounded) is the least valuable, since sapphire does not have enough quality to give facets.
- Weight: Sapphire is relatively abundant stone, so its price is lower than rubies or emeralds. Sapphires above one carat sizes significantly increase its price.
Star of India:
The Star of India is the world's largest with a weight of 563.35 carat star sapphire. Discovered in Sri Lanka about 300 years ago, it is now in the American Museum of Natural History in New York. Grayish-blue color, with a slightly milky quality caused by the presence of rutile. However, the rutile is also responsible for the star effect, effect known as asterism. Apart from its amazing size, the Star of India is also unusual because it has stars on both sides of the stone.
This is one of the oldest known sapphires, 104 carats that dates back to 1214. It has a nice blue color, and the gem has passed through the hands of several kings and cardinals before being mounted in the crown of Queen Victoria . He was eventually replaced by the Star of Africa, so that the sapphire Stuart now rests in the back of the British imperial state crown.