Many purchased minerals are sold in such boxes. Extra care must be exercised when handling and storing them delicate minerals. A badly broken specimen loses its beauty and can become worthless. These fragile minerals should be kept on foam padding or cotton, although acicular , fibrous , and long, slender crystals should be kept away from cotton, as the crystals can get caught in the cotton and break. When cleaning minerals one should use extreme caution.
Several minerals lose their original color when exposed to light for extended periods.
Some minerals, such as kunzite , amethyst , and topaz fade upon prolonged exposure to light. Any mineral that fades should in a dark area or covered box. A few minerals, namely proustite and pyrargyrite, darken upon exposure to light. They darken at a much faster pace than fading minerals fade, and therefore superior care must be taken to keep these specimens away from light. The minerals realgar and orpiment must also be kept out of light.