Crystals may not quite be living, breathing things, but they are gorgeous pieces (sometimes microcosms) of nature and they do require upkeep, rather like a relatively low-maintenance pet. When it comes to crystal care, you want to keep in mind storage, cleaning, and display.
First off, keep your minerals out of direct sunlight, especially those that will crack from the heat or lose their precious pigmentation. Crystals that will damage in sunlight include many varieties of quartz (including clear quartz, which can only withstand two hours in the sun before getting brittle), apatite, apophyllite, aquamarine, aventurine, calcite, celestite, aragonite, barite, beryl, fluorite, orpiment, sodalite, topaz, amazonite, crocoite, diamond, kunzite, lepidolite, and morganite.
Many crystals are also water sensitive. Generally those at a six or above on the Moh’s Harness Scale are safe to get wet – barring special exceptions like malachite or stibnite, which can turn water toxic, or iron ores like pyrite, which can rust. Water-unsafe minerals include fluorite, schorl, selenite, aquamarine, apophyllite, lepidolite, moonstone, amazonite, lapis lazuli, desert rose, opal, azurite, calcite, apatite, malachite, amber, turquoise, labradorite, celestite, pyrite, kyanite, and hematite.
Certain crystals are more delicate and must be treated with extra care. Fiber optic scolecite, for instance, is easily damaged and shouldn’t even be touched if it can be avoided. Stones that are particularly delicate include selenite, azurite, kyanite, fluorite, opal, celestite, turquoise, amber, and aragonite flowers. The Moh’s Hardness Scale can be an indicator of how gently to handle your specimens, but even then, sometimes the arrangement of the cluster can create fragility that goes beyond just hardness or softness. For instance, the tips of crystal points can almost always break off.
On that note, make sure to display your crystals with plenty of space in between the specimens so they are not butting into each other, risking damage like the breaking-off of perfect terminations! If you can keep them behind glass, all the better. Especially for water-unsafe specimens, you can clean them with the kind of aerosol air duster you buy for electronics. Bowls of tumbled stones (unless you have pyrite or malachite in there, of course – always be conscious of what you’re working with!) can be gently cleaned with room-temperature water.
Crystals aren’t just gorgeous freaks of nature, they’re fine art curated by the cosmos and great investment pieces, and proper mineral care is vital to ensuring they remain at their most sparkling and dynamic.