Celestite
What is Celestite?
Celestite is a strontium sulfate mineral, known for its delicate blue crystals, though it can also be found in colorless, white, or other pale hues. It is often found in sedimentary rocks, particularly in association with gypsum, anhydrite, and sulfur deposits. Celestite is prized by collectors for its beautiful crystal formations and is sometimes used as a gemstone.
Optical Properties
- Refractive Index
- nα=1.622-1.628, nβ=1.623-1.630, nγ=1.631-1.639
- Birefringence
- 0.008-0.010
- Pleochroism
- Weak
- Optical Character
- biaxial (+)
- Dispersion
- 0.014
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Celestite 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 Celestite
RockHoundR, the free-to-download rockhounding map from the Ruby Glint team, shows where collectors find celestite in the US, with land-access notes for BLM land and national forests. Collecting is banned in national parks.
See where to find celestiteAlways check the local rules and get the landowner's permission before you collect.
Quick Facts
Physical Properties
- Color
- Colorless, white, pale blue, light green, reddish
- Hardness (Mohs)
- 3 - 3.5
- Rock tumbling
- Not recommended
- Density
- 3.97 - 4.05 g/cm³
- Streak
- White
Chemical Properties
- Chemical Formula
- SrSO₄
- Elements
- Sulfur, Oxygen, Strontium
Also Known As
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Celestite FAQs
How do I identify Celestite?
Celestite can be identified by its hardness of 3 - 3.5 on the Mohs scale, Colorless color. Look for these key characteristics when examining specimens.
What color is Celestite?
Celestite typically appears in Colorless, white, pale blue, light green, reddish. Color can vary depending on impurities and formation conditions.
How hard is Celestite?
Celestite has a hardness of 3 - 3.5 on the Mohs scale. This makes it a soft mineral that can be scratched easily.