Tree Agate
A variety of Chalcedony
What is Tree Agate?
Also known as dendritic agate, tree Agate has been known to humanity since ancient times: It was a favorite carving stone for seals and rings among the ancient Egyptians, and the ancient Greeks would bury this stone to promote plentiful harvests in the coming season. It is named for its foliage-like patterns.
Optical Properties
- Refractive Index
- 1.530-1.543
- Birefringence
- 0.003-0.009
- 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 Tree 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 Tree Agate
Tree Agate is a variety of Chalcedony. RockHoundR, the free-to-download rockhounding map from the Ruby Glint team, shows where collectors find chalcedony in the US, with land-access notes for BLM land and national forests. Collecting is banned in national parks.
See where to find chalcedonyAlways check the local rules and get the landowner's permission before you collect.
Health & Safety Information
- ⚠️Tree 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.
- ⚠️Tree 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 tree Agate, be sure to wear a dust mask to avoid inhaling its dust.
Quick Facts
Physical Properties
- Color
- White with green patches
- Hardness (Mohs)
- 6.5 - 7
- Rock tumbling
- Tumbles well
- Density
- 2.6 g/cm³
- Streak
- White
- Luster
- Waxy, Vitreous
- Crystal System
- Trigonal
Chemical Properties
- Chemical Formula
- SiO2
- Elements
- O, Si
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Tree Agate FAQs
How do I identify Tree Agate?
Tree Agate can be identified by its hardness of 6.5 - 7 on the Mohs scale, White with green patches color, Waxy, Vitreous luster, Trigonal crystal system. Look for these key characteristics when examining specimens.
What color is Tree Agate?
Tree Agate typically appears in White with green patches. Color can vary depending on impurities and formation conditions.
How hard is Tree Agate?
Tree Agate has a hardness of 6.5 - 7 on the Mohs scale. This gives it moderate hardness.