According to Yang Ming Jewelry and Wikipedia, Siam sapphire is an extremely deep blue to blue-black sapphire, which originated in Thailand (formerly known as Siam) and was later used to refer to sapphires with similar colors in other places of origin. In Britain, the meaning of Siam sapphire is slightly different, and it is often used to refer to a very dark blue sapphire with a little velvet, which is not as good as Kashmir sapphire. The value of Siam sapphire mainly depends on its color, transparency, cut, weight and purity. Generally speaking, the darker the color, the more saturated it is, the higher the transparency, the finer the cutting, the greater the weight, the higher the purity and the higher the value. Of course, different markets and consumers will have different preferences for colors, and some people may prefer lighter or lighter colors. In addition, whether it is natural or artificial will also affect the value. Natural Siamese sapphires are usually more expensive than artificial ones. The price of Siam sapphire is about $0/00 to $0/000 per carat/kloc, depending on its quality. For example, a natural Siamese sapphire weighing about 1.5 carats, dark blue in color, with a transparency of VS (very tiny inclusions) and cut with a round diamond section costs about $500; An artificial Siamese sapphire weighing about 2.5 carats, dark blue and black in color, with a transparency of Si (tiny inclusions) and an oval diamond section, costs about $65,438+000.