Do you happen to have an inner geologist within you? If you have answered in the affirmative, then you would surely be pleased as punch to check out this $4.99 Retro Rocks & Minerals Collection. It will do its bit to encourage the budding geologist inside of you, where there are more than 20 common rocks and minerals from around the USA to enjoy. Granted, it can be rather tricky at first to figure out whether something is a mineral or a rock, especially where a casual observer is concerned, but to a geologist, a rock is worlds apart from that of a mineral. In fact, here is the lowdown so that you can look smart to your mates – a mineral is a combination of two or more elements, while a rock would be a combination of 2 or more minerals, now how about that?