Entry № 200
Garnet in Biotite
Almandine in Biotite Schist
Metamorphic proof that pressure produces jewels.
Chakra
Root · Solar Plexus
Element
Fire · Earth
Zodiac
Aries · Capricorn

I. The Metaphysical Reading
How the stone has been held.
Garnet in biotite is worked with as a stone of endured work, carried through training, apprenticeships and slow projects. Practitioners hold that the biotite records the layered effort while the garnet marks the moments where that effort became structure.
- Chakra
- Root · Solar Plexus
- Element
- Fire · Earth
- Zodiac
- Aries · Capricorn
- Keynote
- Metamorphic proof that pressure produces jewels.
II. The Scientific Reading
What the lattice actually does.
Garnet-biotite schist is one of the most iconic index-mineral assemblages in metamorphic petrology. Almandine porphyroblasts nucleate and grow within a foliated biotite matrix as the parent pelite crosses the garnet-biotite isograd, typically at temperatures around 500 – 600 °C. Geologists use the composition of coexisting garnet and biotite as a classic geothermometer.
- Formula
- Almandine Fe₃Al₂(SiO₄)₃ in biotite K(Mg,Fe)₃AlSi₃O₁₀(OH,F)₂
- System
- Aggregate (isometric garnet in monoclinic mica schist)
- Hardness
- 2.5 – 7.5 (Mohs, mica soft / garnet hard)
- Provenance
- USA (New England, Idaho), India, Norway, Australia
References & Sources
Independent mineralogical references used to verify the scientific details above.
Mineral Profile
Fact Sheet
- Chemical Formula
- Almandine Fe₃Al₂(SiO₄)₃ in biotite K(Mg,Fe)₃AlSi₃O₁₀(OH,F)₂
- Crystal System
- Aggregate (isometric garnet in monoclinic mica schist)
- Mohs Hardness
- 2.5 – 7.5 (Mohs, mica soft / garnet hard)
- Density
- 2.80 – 3.30 g/cm³
- Refractive Index
- 1.57 – 1.83 (bulk)
- Provenance
- USA (New England, Idaho), India, Norway, Australia
- Color Origin
- Dark brown-black biotite matrix with deep red almandine porphyroblasts
Related Crystals
Stones that share this lattice
Next in the Atlas
Garnet in Staurolite
Two crystal habits that only share a schist.




