Precious metals, like sterling silver, will not be attracted to the magnet. If your silver is sterling, you will also notice a mark on the piece. This mark might state .925, sterling, or ster. If there is no marking on the piece, it might not be sterling silver.
Costume jewelry should be taken care of. A lot of the stones in costume jewelery are glued in and not set in. Therefore, you shouldn't get costume jewelry wet or expose it to harsh chemicals. To care for it best, wipe your jewelry with a damp, warm cloth and dry it with a different cloth. This will make your costume jewelry sparkle for weeks, months, or even years.
Keep all of your jewelry cleaner by putting it on only after you have applied all makeup and perfume. The sparkle of a piece of jewelry is a magnet for loose or wet makeup, which will leave it tarnished and dingy. This is particularly important in the case of necklaces and earrings.
Gems are given chemical treatments in the process of cutting, polishing and setting. When you are thinking of buying, ask what treatment a stone was given. The way to care for a stone differs greatly depending on how it was treated. You want to avoid putting a solution on jewelry that has been treated, particularly if you do not know whether or not it will hurt the piece.