Natural Gemstones

Natural Gemstones, from the U.S. Geological Survey, says that searching for gemstones in the United States is a popular recreational activity for collectors and hobbyists. The text defines a natural gemstone as a mineral, stone, or organic matter that can be cut and polished or otherwise treated for use as jewelry or other ornament. The text says a precious gemstone has beauty, durability, and rarity, whereas a semiprecious gemstone has only one or two of these qualities.

The text says the average grade of the richest diamond kimberlite pipes in Africa is about 1 part diamond in 40 million parts ore. The text says diamond, corundum (ruby and sapphire), beryl (emerald and aquamarine), topaz, and opal are generally classed as precious stones. The text says owners of land that has a deposit of gem-quality minerals sometimes charge hobbyists for the right to collect gemstones, for example diamond in Arkansas, opal in Idaho, and agate in Oregon and Washington. The text says several kinds of natural gemstones have been found in every State of the United States.