The Aquamarine Gemstone is a 7.5 - 8 on the Moh's Scale of Hardness. It is a good gemstone for use in rings, pendants and earrings. Clean your Aquamarine in an ultrasonic jewelery cleaner or with warm, soapy water and a soft tooth or Sulcabrush. Do not clean in a home ultrasonic machine. As with all gemstones, care should be taken to protect it from scratches and sharp blows. Aquamarine often pales if left out in the sun.