อย่างไรก็ตาม, this pair of gem “พี่สาวน้องสาว” is not like the “husband and wife mine” realgar and orpiment, ที่ “twin mine” galena and sphalerite often coexist together, but often live on one side. The reason is that the two are formed in different environments: rubies are mostly produced under geological and geochemical conditions that are high […]
