Ferro-holmquistite
A variety of Holmquistite Root Name Group
What is Ferro-holmquistite?
Holmquistite is a lithium magnesium aluminium inosilicate mineral with chemical formula Li2(Mg,Fe2+)3Al2Si8O22(OH)2. It crystallizes in the orthorhombic crystal system as prismatic crystals up to 10 cm (3.9 in) or as massive aggregates. It has a Mohs hardness of 5-6 and a specific gravity of 2.95 to 3.13. Color could vary from black, dark violet to light sky blue. It occurs as metasomatic replacements on the margins of lithium rich pegmatites. It was first described in 1913 from an occurrence in Utö, near Stockholm, Sweden. It was named for the Swedish petrologist Per Johan Holmquist (1866–1946).
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Ferro-holmquistite 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.
Ferro-holmquistite Localities Map
See where Ferro-holmquistite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Quick Facts
Physical Properties
- Color
- Black, dark-violet, light sky-blue.
- Hardness (Mohs)
- 5 - 6
- Density
- 3.145 g/cm³
- Streak
- White with a sky-blue tinge (?)
Chemical Properties
- Chemical Formula
- ☐{Li2}{Fe2+3Al2}(Si8O22)(OH)2 The holmquistite group comprises orthorhombic amphiboles in the lithium amphibole subgroup. Holmquistite is defined with Fe2+Mg and Al>Fe3+ in the C position.
- Elements
- Al, Fe, H, Li, O, Si
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Ferro-holmquistite FAQs
How do I identify Ferro-holmquistite?
Ferro-holmquistite can be identified by its hardness of 5 - 6 on the Mohs scale, Black color. Look for these key characteristics when examining specimens.
What color is Ferro-holmquistite?
Ferro-holmquistite typically appears in Black, dark-violet, light sky-blue.. Color can vary depending on impurities and formation conditions.
How hard is Ferro-holmquistite?
Ferro-holmquistite has a hardness of 5 - 6 on the Mohs scale. This gives it moderate hardness.