Although crystals are fairly hearty, they are made of glass and as such, can chip. Those with an AB (Aurora Borealis) reflective finish can scratch. Bracelets are particularly susceptible to chipping. Just be careful and you should be fine.

Silver is a beautiful metal but does tarnish. This process is accelerated when exposed to air or especially humidity. Store your silver pieces in a cloth or ziploc bag.
There are different methods for cleaning silver. A special polishing cloth works well on charms but is difficult to use on chains and wires.
The following cleaning information is taken from the Land of Odds website. It is followed by other websites to check out.

We at Land of Odds get many questions about how to clean silver jewelry, liquid silver jewelry, marcasite jewelry, and jewelry with gemstones. We're silversmiths, and we have a shop where we sell sterling silver jewelry, as well as beads and jewelry findings.

Nothing is perfect, but based on our experiences, here are some good tips:
(1) Sterling Silver tarnishes from the interaction of silver and sulfides in the air.   First the tarnish will take on a golden hue, and eventually, it will turn the piece black.  This is a natural process.

Higher sulfide levels are associated with humidity and/or air pollution. Remember, the more humid the climate, the faster sterling will tarnish. On a summer day in Miami, Florida, all you have to do is walk out the door and the sterling starts turning black very quickly.
(2) Sterling silver will polish up by rubbing or buffing it with a soft cotton cloth. A chemically treated cloth, like a Sunshine Cloth, makes the job a lot easier and faster.
(3) Sterling silver dips are fast and easy. However, be careful! First, many dips will take the color and polish off many gemstones.
Second, when using a dip, if you leave the piece in too long, or don't rinse it well enough with fresh water, white residues will be left on the piece when it dries. The residue is difficult to rub or pick off.

When using a silver dip, dip the piece quickly in and out of the dip. Then immediately rinse it in clean water. When the piece dries, buff it with a soft cotton cloth or a Sunshine Cloth. The buffing brings out more of the shine, helps take off any residue left on the piece, and with a Sunshine Cloth, leaves a little bit of a protective anti-tarnish coating on the piece to keep it shiny longer.
When using a dip, it is better to do an in-and-out dip, then rinse and dry, then another quick in-and-out-dip, then rinse and dry, than to leave the piece in the solution for a long time.
We use a dip - Rey's Tarnish Remover - which works better, and has less of a residue problem, than many dips you'll find in your local drugstore, like Tarn-X.  Any dip, however, including Rey's, is a last resort.  The piece would have to be very difficult to buff up with a soft cloth.

If you would like to make your own solution, check out a good article I found on cleaning silver jewelry.