Amethyst, Citrine, Tourmaline, Aquamarine, Peridot,
Alexandrite, and Morganite
These stones have a hardness of 7 - 8.5 on the Mohs' Scale. Some are more brittle than others and care will vary somewhat for these specific stones. You should ask your jeweler at time of purchase. All of the stones listed above can be cleaned while in their mountings with a commercial jewelry cleaner or visit your favorite jeweler for maximum cleaning with an ultrasonic and a steam cleaner.
Know your stones! For example there is a specific name that is used for each of the many colors of the rainbow stone known as tourmaline. Verdelite is the yellowish green tourmaline. All of these stones must be removed from their mountings for retipping and for undercarriage and other repairs near them. They will crack with heat, even though some are heat treated for maximum color saturation. This is done in a very controlled environment and over a long period of time, with no exposure to air.
