Staurolite
Iron–aluminium metamorphic silicate often recognised by characteristic cruciform crystal twins.
Language and route: European scientific form from Ancient Greek σταυρός (staurós), cross, and λίθος (líthos), stone. European scientific form from Ancient Greek σταυρός (staurós), cross, and λίθος (líthos), stone
Literal gloss: cross-stone
The name and its history
Old Greek-rooted mineral name; priority unresolved · First specific geological publication not confirmed
- What does the word literally mean?
- Immediate borrowing or word-formation route: European scientific form from Ancient Greek σταυρός (staurós), cross, and λίθος (líthos), stone. Source form: σταυρός (staurós), glossed ‘cross’. Conventional short gloss: ‘cross-stone’. A literal gloss and the historical reason for naming must be distinguished.
- What did the original author mean?
- Cross-stone vocabulary is older than Barrovian index-zone schemes; exact first printed staurolite naming act remains unresolved.
- Why was the name needed?
- Mineralogists sought to identify a striking twinned crystal habit among similarly coloured silicates.
- What evidence supported the original concept?
- Hand specimens revealed 60°/90° crossing twins and hardness; original naming did not establish a metamorphic grade.
- How has geology changed the concept?
- Staurolite assemblages help constrain reaction histories, but its presence alone does not measure a unique pressure or temperature.
Further historical context
Cross-stone vocabulary is older than Barrovian index-zone schemes; exact first printed staurolite naming act remains unresolved.
Mineralogists sought to identify a striking twinned crystal habit among similarly coloured silicates.
Hand specimens revealed 60°/90° crossing twins and hardness; original naming did not establish a metamorphic grade.
Staurolite assemblages help constrain reaction histories, but its presence alone does not measure a unique pressure or temperature.
Editorial qualification
Original naming passage has not been independently transcribed; a later nomenclatural account cannot by itself establish first coinage.
Related names
Sources
- Mindat — Staurolite — cross-shaped twinning etymology and mineral species context
- Smith College — Aluminium silicate phase diagram — modern Al2SiO5 pressure-temperature stability fields, model dependent
- IUGS recommendations on high-pressure rocks — modern assemblage versus facies naming safeguards