Blue Chalcedony
A variety of Chalcedony
What is Blue Chalcedony?
Blue Chalcedony is a highly prized gemstone. The blue variety of Chalcedony occurs only when it does not contain many color-changing impurities. This stone is perfect for carving, cutting, crafting, and tumbling, and its rarity may explain why so many Chalcedonies are artificially colored for the market. The most valuable natural specimens of blue Chalcedony bend the light in such a way that they appear to be lit from within.
Optical Properties
- Refractive Index
- 1.530-1.543
- Birefringence
- 0.003-0.009
- Pleochroism
- None
- Optical Character
- Biaxial positive
- Dispersion
- 0.013
Discover Values
This stone excels in beauty.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Blue Chalcedony 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.
Blue Chalcedony Localities Map
See where Blue Chalcedony is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Health & Safety Information
- ⚠️Blue Chalcedony 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.
- ⚠️Blue Chalcedony 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 blue Chalcedony, be sure to wear a dust mask to avoid inhaling its dust.
Quick Facts
Physical Properties
- Color
- Blue
- Hardness (Mohs)
- 6.5 - 7
- Density
- 2.55 - 2.7 g/cm³
- Streak
- White
- Luster
- Waxy
- Crystal System
- Trigonal
Chemical Properties
- Chemical Formula
- SiO2
- Elements
- O, Si
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Blue Chalcedony FAQs
How do I identify Blue Chalcedony?
Blue Chalcedony can be identified by its hardness of 6.5 - 7 on the Mohs scale, Blue color, Waxy luster, Trigonal crystal system. Look for these key characteristics when examining specimens.
What color is Blue Chalcedony?
Blue Chalcedony typically appears in Blue. Color can vary depending on impurities and formation conditions.
How hard is Blue Chalcedony?
Blue Chalcedony has a hardness of 6.5 - 7 on the Mohs scale. This gives it moderate hardness.