Cleaning your crystals can be a little tricky. With so many variations of chemical constituents it is best to use caution as some crystals can be badly affected by water especially salt water. Selenite for example will dissolve if left in water. Others like Angelite/Anhydrite will start to morph into other crystals, in this case Gypsum.

Some crystals contain toxic compounds which are bioactive & released by water, Malachite & Calcanthite are both bioactive copper minerals. This means they are potentially dangerous & need to be handled with care, best to not wet them.   

Minerals like Opal & Orpiment are hydrous. They need to retain a certain amount of water to maintain mineral structure. Orpiment contains Arsenic which is released in dust/powder form when the mineral dries out (Keep in a zip lock bag or airtight container to manage risk of exposure)

The vibrant colours of Amethyst, Agate & Chalcedony will fade quickly when exposed to sunlight.  

There are many many other crystals which have special needs the above is just a short example. To play it safe we recommend smudging with sage, using white light, vibrational resonance, the full moon or other crystals for energy cleansing. Carnelian, Selenite & Citrine will cleanse the energy of other crystals & themselves

For physically cleaning a dusty crystal look into that crystals specific handling requirements we often use a camera lens blower on delicate unwashable crystals.

Crystal jewellery must be handled with care and never exposed to water especially salt water, DO NOT wear crystal jewellery in the shower or swim with it & do not expose jewellery to chemicals.    

There is no need to be scared of toxic crystals, just find the info you need. 

Don't be afraid be educated! If in doubt seek professional advice.