Cracked rock crystal is a treated quartz that is first shocked by high heat and then rapidly cooled. This causes thin cracks to run through the stone, affecting its appearance and reflecting light. When in contact with skin oils, for example, these can penetrate the stone and affect its appearance, making it look brighter than it really is. If you want to keep the cracked appearance for a long time, we recommend avoiding contact with oils etc. and that it is used on a long chain.