[header] How to buy an opal [title] Familiarize yourself with opals and their terminology. [step] Opals differ from other precious gemstones in their basic composition and how they are valued. These unique stones come in a wide range of colors and patterns, both of which can change, depending on the angle you view them from. 
Since buying an opal can be a significant investment, learn as much as you can about them before you start shopping. This will ensure you make an informed decision and get what you pay for.