Grape Agate
Grape Agate Chalcedony
A variety of Chalcedony
What is Grape Agate?
Grape Agate is not actually an agate at all. Grape Agate is a type of quartz that forms in clusters of light and dark purple spheres, resembling grapes. Its name has been enhanced for marketing purposes.
Optical Properties
- Refractive Index
- 1.530-1.543
- Birefringence
- 0.003-0.009
- Pleochroism
- None
- Optical Character
- Biaxial positive
- Dispersion
- 0.013
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Grape 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.
Grape Agate Localities Map
See where Grape Agate is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Health & Safety Information
- ⚠️Grape 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.
- ⚠️Grape 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 grape Agate, be sure to wear a dust mask to avoid inhaling its dust.
Quick Facts
Physical Properties
- Color
- Deep purple to very pale amethystine or whitish, violet, green, purple, green
- Hardness (Mohs)
- 6.5 - 7
- Density
- 2.55 - 2.7 g/cm³
- Streak
- White
- Luster
- Waxy, Vitreous
- Crystal System
- Trigonal
Chemical Properties
- Chemical Formula
- SiO2
- Elements
- Si, O
Also Known As
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Grape Agate FAQs
How do I identify Grape Agate?
Grape Agate can be identified by its hardness of 6.5 - 7 on the Mohs scale, Deep purple to very pale amethystine or whitish color, Waxy, Vitreous luster, Trigonal crystal system. Look for these key characteristics when examining specimens.
What color is Grape Agate?
Grape Agate typically appears in Deep purple to very pale amethystine or whitish, violet, green, purple, green. Color can vary depending on impurities and formation conditions.
How hard is Grape Agate?
Grape Agate has a hardness of 6.5 - 7 on the Mohs scale. This gives it moderate hardness.