Bertrandite
A variety of Minerals
What is Bertrandite?
Bertrandite is a beryllium sorosilicate hydroxide mineral with composition: Be4Si2O7(OH)2. Bertrandite is a colorless to pale yellow orthorhombic mineral with a hardness of 6-7. It is commonly found in beryllium rich pegmatites and is in part an alteration of beryl. Bertrandite often occurs as a pseudomorphic replacement of beryl. Associated minerals include beryl, phenakite, herderite, tourmaline, muscovite, fluorite and quartz. It, with beryl, are ores of beryllium. It was discovered near Nantes, France in 1883 and named after French mineralogist, Emile Bertrand (1844–1909). One of the world's largest deposits of bertrandite is Spor Mountain, Thomas Range, Utah which is currently the source of most of the world's beryllium production.
Optical Properties
- Refractive Index
- 1.583-1.614
- Optical Character
- Biaxial negative
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Bertrandite 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.
Bertrandite Localities Map
See where Bertrandite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Colourless, pale yellow
- Hardness (Mohs)
- 6 - 7
- Density
- 2.61 g/cm³
- Streak
- White
Chemical Properties
- Chemical Formula
- Be4(Si2O7)(OH)2
- Elements
- Be, H, O, Si
Identify Bertrandite Instantly
- Snap a photo, get instant results
- 6,700+ rocks, minerals & crystals
- Discover collecting spots near you
Bertrandite FAQs
How do I identify Bertrandite?
Bertrandite can be identified by its hardness of 6 - 7 on the Mohs scale, Colourless color. Look for these key characteristics when examining specimens.
What color is Bertrandite?
Bertrandite typically appears in Colourless, pale yellow. Color can vary depending on impurities and formation conditions.
How hard is Bertrandite?
Bertrandite has a hardness of 6 - 7 on the Mohs scale. This gives it moderate hardness.
%252FAbenakiite-(ce)-01.jpg&size=small)
