precious gemstones

There is no globally approved grading standard for gemstones. The Gemological Institute of America designed a method for grading diamonds in the early 19th century. Previously, all diamonds were graded solely by sight. The use of a magnification value of 10x as the threshold for judging clarity was a key advance in the GIA method. Other […]

Most precious gemstones are formed in nature through the unique power of the planet involving a combination of huge pressure, minerals and heat generally coming from tectonic plate movement or volcanic activity. The process of gemstone created in this way is called metamorphism. Historically people have valued and admired gemstones due to various facts including