Moss Agate
Green Moss Agate
A variety of Chalcedony
What is Moss Agate?
Moss Agate is a translucent Agate (a type of Chalcedony) that features a mossy, dendric, branching, or fern-like pattern, thus the name. With these unusual patterns, this semi-precious stone gives an impression of a small landscape or tree captured inside of the stone. Moss Agate makes wonderful tumbled stones and is often used for beads and cabochons.
Optical Properties
- Refractive Index
- 1.530-1.540
- Birefringence
- 0.004
- Pleochroism
- None
- Optical Character
- Biaxial positive
- Dispersion
- 0.013
Discover Values
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Moss Agate before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Where to Find Moss Agate
RockHoundR, the free-to-download rockhounding map from the Ruby Glint team, shows where collectors find moss agate in the US, with land-access notes for BLM land and national forests. Collecting is banned in national parks.
See where to find moss agateAlways check the local rules and get the landowner's permission before you collect.
Health & Safety Information
- ⚠️Moss Agate in powdered form can be toxic due to its Crystalline Silica content.
- ⚠️Quartz, silica, crystalline silica and flint are non-toxic materials, but very fine dust containing quartz, known as respirable crystalline silicon (RCS), can cause serious and fatal lung disease. Lapidaries should exercise caution when cutting silica.
- ⚠️Moss Agate is typically non-toxic unless it's in powder form. Long-term exposure to finely ground powder may lead to silicosis. Therefore, when cutting or polishing moss Agate, be sure to wear a dust mask to avoid inhaling its dust.
Quick Facts
Physical Properties
- Color
- Green
- Hardness (Mohs)
- 6.5 - 7
- Rock tumbling
- Tumbles well
- Density
- 2.6 g/cm³
- Streak
- Green
- Luster
- Waxy, Vitreous
- Crystal System
- Trigonal
Chemical Properties
- Chemical Formula
- SiO2
- Elements
- Si, O
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Moss Agate FAQs
How do I identify Moss Agate?
Moss Agate can be identified by its hardness of 6.5 - 7 on the Mohs scale, Green color, Waxy, Vitreous luster, Trigonal crystal system. Look for these key characteristics when examining specimens.
What color is Moss Agate?
Moss Agate typically appears in Green. Color can vary depending on impurities and formation conditions.
How hard is Moss Agate?
Moss Agate has a hardness of 6.5 - 7 on the Mohs scale. This gives it moderate hardness.