According to data from Hong Kong and Taiwan, Κίνα: Στη διεθνή αγορά κοσμημάτων, the price of high-quality rubies weighing more than 10ct is more than twice that of the best diamonds or emeralds. The chemical composition of ruby and sapphire is aluminum oxide (AI. 0,), which should be colorless when pure. But in nature, […]
