In a word, no. Ultrasonic cleaners clean jewelry by bombarding it with sound waves in a hot solution. The intense vibrations shake dirt free while the heat loosens stuck on grime; however not all fine jewelry and gemstone jewelry can handle the heat and vibrations. Some gemstones will melt or fracture so it is important to know which ones before you put yours in an ultrasonic cleaner.

Even though diamonds tarnish proof jewelry are the hardest gemstone, if yours has been fracture filled, an ultrasonic cleaner could melt the solution in the cracks. When you purchase diamond jewelry, ask your jeweler if the diamond has been fracture filled because it will have a profound effect on the price of the stone. Synthetic diamonds are also too fragile for this method; an ultrasonic cleaner could melt them.

In theory, certain watches should survive an ultrasonic cleaner. The important thing is to know the difference between water-resistant and waterproof. Water-resistant means the outside of the watch repels water. Waterproof means the watch can be immersed in water; however, a watch is graded with water that is room temperature. Another important thing to take into consideration is if the watch's battery has been replaced. In the event that it was, the seal or gasket of the watch may have broken allowing water to seep in and rust the gears.

Certain natural gemstones naturally have a lot of inclusions, such as emeralds. Often these are also fracture filled or oiled so the surface appears uniform. Ultrasonic cleaners are not recommended for emeralds since it will dissolve the oil and possibly crack the stone. Too many inclusions make the stone delicate and susceptible to chipping. Other delicate gemstones include peridot, tanzanites and tourmalines.

Pearls are born in water, sure, but they can also meet their end in the water of an ultrasonic cleaner. The temperature dissolves the pearl's nacre making it appear dull and scratched. Pearls should only be cleaned with a soft cloth. This applies to all pearls including black pearls, chocolate pearls and fresh water pearls.