You can't. Pure gold means that the gold content is not less than 99%. For example, if you buy 100g of gold, at least 99g of it is pure gold, and 1g is impurities. Thousands of pure gold means that the gold content is not less than 99.9%. For example, if you buy 100g of gold, at least 99.9g is pure gold, and the other 0. 1g is impurities. The higher the gold content, the better the quality of gold. Of course, the higher the price.