Where is Moss Agate found?
Chalcedony (cryptocrystalline quartz) with dendritic inclusions of manganese or iron oxides
Got a photo? Identify rocks instantly with the Rockby app
Open the appMoss Agate 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 Moss Agate
India (Deccan Traps)
A primary source, particularly for high-quality green moss agate, found in the extensive basalt flows.
Brazil
Known for various types of agate, including moss agate, often found in volcanic regions.
United States (Montana, Wyoming, Oregon, Washington)
Montana is famous for its 'Montana Moss Agate,' often found in alluvial gravels of the Yellowstone River, characterized by red and brown dendrites. Oregon and Washington also produce moss agate.
Australia
Found in various localities, often associated with volcanic activity.
Russia (Ural Mountains)
Historical source of various agates, including moss agate.
Collecting tips
- Geological Context. Focus on areas with past or present volcanic activity, particularly where basalts or other igneous rocks are weathered or exposed. Look for geodes or vugs in these rocks.
- Alluvial Deposits. Many high-quality moss agates are found as water-worn pebbles and cobbles in riverbeds and gravel deposits, especially downstream from volcanic terrains. Sifting through gravels can be productive.
- Visual Identification. Look for translucent to semi-transparent stones with distinct internal patterns resembling moss, ferns, or trees. The colors of the inclusions can vary (green, black, brown, red).
- Hardness Test. Chalcedony has a Mohs hardness of 6.5-7, so it will scratch glass and steel. This helps differentiate it from softer minerals.
Quick Check
- Color:
- Translucent to opaque white/gray/colorless with green, black, brown, or red moss-like inclusions.
- Luster:
- Waxy to vitreous.
- Streak:
- White.
Explore Moss Agate
Identify rocks anywhere
Free on iOS, Android, and Web. Photo identification, full database, and your personal collection.