Steam or Ultrasonically Clean?

Unsure whether to steam or ultrasonically clean? Reference this handy chart when you need to know how to best clean any faceted gemstone.

Last edited: 12/14/2020

This chart provides general guidelines for the recommended care of quality gemstones. Tiny fractures in stones, even those unseen by the eye, can cause a stone to crack when an ultrasonic cleaner or steam cleaner is used. Additionally, oil treated and dyed gemstones, and composite gemstones such as doublets or triplets should never be cleaned using steam or ultrasonic methods. Care should always be taken—when in doubt your safest cleaning method is a soft brush with soap and water.

Gemstone Mohs Hardness Steam Ultrasonic
Alexandrite 8.5 Usually Usually
Amethyst 7 Never Usually
Apatite 4.5 Never Not Recommended
Aquamarine 7.5-8 Usually Usually
Chalcedony 6.7-7 Usually Usually
Citrine 7 Never Usually
Coral 3.5-4 Never Never
Diamond 10 Usually Usually
Diopside 5.5-6 Never Never
Emerald 7.5-8 Never Never
Garnet 7-7.5 Never Usually
Iolite 7-7.5 Never Never
Jade 6-6.5 Not Recommended Not Recommended
Labradorite 6-6.5 Not Recommended Not Recommended
Lapis 5-5.5 Never Never
Malachite 3.5-4 Never Never
Moonstone 6-6.5 Not Recommended Not Recommended
Morganite 7.5-8 Usually Usually
Opal 5-6.5 Never Never
Pearl 2.5-4.5 Never Never
Peridot 6.5-7 Never risky
Quartz 7 Never Usually
Ruby 9 Usually Usually
Sapphire 9 Usually Usually
Tanzanite 6-7 Never Never
Topaz 8 Never Never
Tourmaline 7-7.5 Never Never
Turquoise 5-6 Never Never

The original source of these recommendations was the GIA (Gemological Institute of America).