Preserve the Crystal in PlasticYou can coat your crystal in plastic to protect it from humidity. For example, you could get a kit that allows you to embed your crystal in lucite or other form of acrylic. A simple, yet effective method of preserving many crystals is to coat them with a few layers of clear nail polish or floor polish (e.g., Future). Be careful using nail polish or especially floor wax because these products may dissolve the top layer of your crystals. Be gentle when applying the coatings and allow each coating to dry completely before adding another layer.
Preserving a crystal by coating it in acrylic or another plastic also helps to protect the crystal from being scratched or shattered. Many crystals that are grown in water may be either brittle or else soft. Plastic helps to stabilize the structure, protecting the crystal from mechanical damage.
Crystals in JewelryHowever, this doesn't turn your crystal into a diamond! It's still a good idea to protect your crystal from direct contact with water (e.g., treat is as water-resistant and not water-proof) or rough handling. In some cases you may be able to set a protected crystal as a gem for jewelry, but I advise against using these crystals in rings or bracelets because the crystal will get knocked around more than if it was set into a pendant or earrings. Don't set toxic crystals for use as jewelry, just in case a child gets hold of the crystal and places it in her mouth.
Storage TipsWhether or not you apply a treatment to your crystal, you'll want to store it away from common sources of damage.
Many crystals react to heat and light. Keep your crystals away from direct sunlight. If you can, avoid exposure to other sources of high energy synthetic light, such as fluorescent bulbs. If you must light your crystal, try to use indirect, cool lighting.
While you might guess that heat could damage your crystal, did you know cold is dangerous, too? Many homegrown crystals are water-based, so if the temperature dips below freezing the water in the crystals could freeze. Because water expands when it freezes, this can crack a crystal. Cycles of heating and cooling are especially bad, since they cause the crystal to expand and contract.
It's easy to keep dust off of a crystal than to try to remove it, especially if the crystal is fragile. Keep your crystal in a sealed container or else wrap it in tissue or store it in sawdust. All of these options will help keep your crystal from accumulating dust and grime. If you do need to dust a crystal, try to use a dry or very slightly damp cloth. Too much moisture could cause you to wipe away the top layer of your crystal along with the dust.
Good Crystals To GrowAlum Crystals
Blue Copper Sulfate Crystals
Purple Chrome Alum Crystals