Gemstone Care: Dolomite

I thought since there are several pairs of Dolomite in the next shop update, it would be good to start my Gemstone Care series with this one!

Red Freckle Dolomite / Red Dalmation Dolomite / Red Spotted Gray Dolomite

Gemological Information

Species: Dolostone

Variety: -

Trade Name(s): Dolomite, Sunset Dolomite (pictured, left), Red Freckle/Red Dalmatian Dolomite (pictured, right).

Mohs Hardness: 3.5 to 4.0

Toughness: Very poor to fair
Durability: Fair

Heat -- thermal shock can cause stone to fracture (crack).
Chemicals -- attacked by hydrochloric acid

* * *

Dolostone is a sedimentary carbonate rock that contains a high percentage of the single mineral dolomite, a calcium magnesium carbonate [ CaMg(CO₃) ]. The mineral dolomite ranges in color from colorless, white, gray, reddish-white, brownish-white, or pink. In the rock materials pictured above, the trace element Manganese (Mn) gives the stone its pinkish to red hues; traces of the element Iron (Fe) contribute to yellow to orange to brown hues.

Regarding Hardness:
In my experience cutting and setting dolostone, this material is extremely soft — softer than turquoise, variscite, or opal.

  • Protect the stone's surface during setting
  • Avoid contact with abrasives (sandpaper, pumice wheels, etc.)
  • Avoid contact with files

Regarding Toughness:
Both types of dolomite pictured above can and will fracture with too much pressure applied, specifically along inclusions such as the manganese oxide dendrites in the Sunset Dolomite, or near the red "spots" in the Red Freckle Dolomite.

  • Avoid dropping
  • Avoid sharp blows when setting
  • Take your time and keep pressure evenly distributed around the stone when setting

Regarding Durability:

  • Avoid exposure to heat, may fracture
  • Avoid exposure to acids, such as the pickle pot, may dissolve the stone or its inclusions
  • Avoid exposure to chemicals used in ultrasonic cleaning solutions, may dissolve parts of the stone or its inclusions


Care and Cleaning
Warm, soapy water - Safe.
Ultrasonic cleaning - May fracture and/or dissolve.
Steam cleaning - Risk of fracture.


Glossary of Terms Used

Durability—A gemstone’s ability to withstand wear, heat, and chemicals.

Gem Species—A broad gem category based on chemical composition and crystal structure.

Gem Variety—A subcategory of species, based on color, transparency, or phenomenon.

Hardness—How well a gemstone resists scratches. Usually expressed in terms of the Mohs scale, with diamond the hardest (10) and talc the softest (1).

Inclusion—A characteristic enclosed within a gemstone, or reaching its surface from the interior.

Mineral—A natural, inorganic substance with a characteristic chemical composition and usually characteristic structure.

Mohs ScaleA scale of hardness used in classifying minerals. It runs from 1 to 10 using a series of reference minerals, and position on the scale depends on ability to scratch minerals rated lower.

Rock—A natural material composed of masses of mineral crystals of one or more kinds.

Sedimentary rock—Rock produced by the accumulation or deposition of eroded and weathered remains of existing rocks.

Thermal Shock—Damage caused by sudden, extreme temperature changes.

Toughness—How well a gemstone resists breaking and chipping.

Trace elements—Atoms in a gem that aren’t part of its essential chemical composition.


#dolomite #dolostone #GemstoneCare #ManganeseOxide #calcite

Back to blog