Where is Dolomite found?
CaMg(CO3)2
Got a photo? Identify rocks instantly with the Rockby app
Open the appDolomite occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.
Where to find Dolomite
Dolomite Alps, Italy
The type locality for the mineral and rock, known for its spectacular mountain ranges composed largely of dolostone.
Midwestern United States (e.g., Illinois, Wisconsin, Missouri)
Extensive dolostone formations are found in these regions, particularly in Paleozoic strata, used for construction and industrial purposes.
Ontario, Canada
Significant deposits of dolostone are quarried for various applications.
Spain
Known for well-formed, often pinkish dolomite crystals.
Collecting tips
- Acid Test. Dolomite reacts weakly with dilute hydrochloric acid (HCl) when cold and in massive form, often requiring scratching to produce effervescence. Calcite, in contrast, effervesces vigorously. This is a key distinguishing test.
- Crystal Habit. Look for characteristic saddle-shaped rhombohedral crystals, which are a strong indicator of dolomite.
- Hardness. Dolomite is slightly harder than calcite (3.5-4 vs. 3 on Mohs scale), which can be tested with a steel nail (hardness ~5.5). Dolomite will scratch calcite, but calcite will not scratch dolomite.
Quick Check
- Color:
- White, gray, pink, tan (common)
- Luster:
- Vitreous to pearly
- Streak:
- White
Explore Dolomite
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.