It sounds like your jewelry needs to be cleaned. We recommend that you clean your jewelry often to keep dirt away from the stones.
If your silver jewelry has black spots, the silver has begun to oxidize. Here we recommend using a silver cleaner or a silver cloth to make the jewelry clean and clear again.
To clean the stones, we recommend putting the jewelry in soap and water for a few hours and then cleaning the jewelry with a toothbrush as it can be difficult to get to the dirt that has settled under the stones.
Read more in our full guide to jewelry care and cleaning.