For all crystals: Avoid direct and bright sunlight, high temperatures and low temperatures. This could affect the color of the stone. All crystals have such a high energy-frequency that they won’t have to be energetically cleaned or charged.
For pendants: Due to heat or warm water, the glue of the top could possibly dissolve. In this case, I recommend you to glue the top with a strong two-component glue of good quality. Due to the smooth surface I recommend a glue that is suitable for glass.
The tops are silver-plated. Direct skin contact, rough surfaces, etc could affect the silver. In that case I recommend you to use an invisible varnish.