Bull's Eye
A variety of Tiger's Eye
What is Bull's Eye?
Bull's Eye is used for jewelry material. As a member of the Quartzite group, these stones offer beautiful red and brown colorations. This coloring can be enhanced with artificial dyes.
Optical Properties
- Refractive Index
- 1.534-1.540
- Birefringence
- 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 Bull's Eye 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.
Bull's Eye Localities Map
See where Bull's Eye is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Health & Safety Information
- ⚠️Bull's Eye in powdered form can be toxic due to its Crocidolite Asbestos, Crystalline Silica content.
- ⚠️Beware of asbestos. Inhalation of asbestos fibres can lead to various dangerous lung conditions, including mesothelioma, asbestosis, and lung cancer. And it can take years for symptoms related to the exposure to appear. Lapidaries should exercise caution when cutting this mineral.
- ⚠️Bull's Eye is typically non-toxic except in powder form. If you plan to cut or polish bull's Eye, it's advisable to wear a dust mask to avoid inhaling any dust. Asbestos fibers and silica dust are hazardous when inhaled, as they can lead to serious lung disease.
Quick Facts
Physical Properties
- Color
- Red, brown
- Hardness (Mohs)
- 6.5 - 7
- Density
- 2.64 - 2.69 g/cm³
- Streak
- Yellow-Brown
- Luster
- Silky, Vitreous
- Crystal System
- Trigonal
Chemical Properties
- Chemical Formula
- SiO2
- Elements
- O, Si
Also Known As
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Bull's Eye FAQs
How do I identify Bull's Eye?
Bull's Eye can be identified by its hardness of 6.5 - 7 on the Mohs scale, Red color, Silky, Vitreous luster, Trigonal crystal system. Look for these key characteristics when examining specimens.
What color is Bull's Eye?
Bull's Eye typically appears in Red, brown. Color can vary depending on impurities and formation conditions.
How hard is Bull's Eye?
Bull's Eye has a hardness of 6.5 - 7 on the Mohs scale. This gives it moderate hardness.