It's always fun to go rockhounding and digging your own mineral specimens. If the stones look promising to you in terms of color, clarity, size, and shape, let a good gemcutter have a look at them. The preliminary examination is usually at no cost. Stones can be cut very inexpensively in various third world sweatshops, but it's often prohibitive to do this unless you're working with large numbers of stones and can wait several months for their return. Someone said I could have it polished, and yet when I asked at a local jewelry store, they said they had never heard of doing any such thing.
Opals are soft and like many other stones can become scratched and dull-looking over time.
Usually they can be repolished at low cost with little or no weight loss. Show it to a good gemcutter for an expert opinion. For example, any and all information that pertains to Topaz. It's for a science project for my son. I appreciate your help.