Chlorite
A group of sheet-silicate minerals; many species have characteristic green colours.
Language and route: English mineral name from Latinised Greek chlorītēs, reused in German mineralogy. Ancient Greek khlōrós ‘pale green’ → khlōrîtēs ‘green stone’ → later European mineralogical chlorite.
Literal gloss: green stone (historical); greenish
The name and its history
Abraham Gottlob Werner (historical name attribution; date contested) · Werner 1789 or 1798 in competing historical sources
- What does the word literally mean?
- The root describes colour, not the mineral structure. A stone called chlorites was known in antiquity; the modern chlorite group is a distinct technical category. Historical reference works conflict over whether Werner applied Chlorit in 1789 or 1798, and original editions require collation.
- What did the original author mean?
- Chlorites was already a classical word for a green stone, and English sources used it before Werner. Werner reused a green-mineral label in his late eighteenth-century mineral system; retrospective references disagree between 1789 and 1798 for his particular designation.
- Why was the name needed?
- A workable name was needed for greenish micaceous minerals before chemistry resolved their mineral diversity.
- What evidence supported the original concept?
- The historical Oxford English Dictionary cites a 1601 translation of Pliny using chlorites, an English mineralogical use in Kirwan (1794), and Werner's specific use in 1789; the 1911 Encyclopædia Britannica instead dates Werner to 1798. These are not evidence of first classical coinage.
- How has geology changed the concept?
- The term became a mineral group, not the name of every green stone. Improved chemical and crystallographic investigation separated multiple phyllosilicate species; colour is not a sufficient diagnosis.
Further historical context
A. G. Werner applied the name to greenish minerals in the late eighteenth century, when visual, physical and chemical observations were still being organised into mineral species. An early nineteenth-century use of chlorite could denote an assemblage later divided into several species rather than the group as now understood.
Von Kobell’s work in 1838 and later crystallographic and compositional analyses subdivided the historical material. A name once associated with colour is now a group designation for related sheet-silicates; not every green rock contains chlorite, and not all chlorite-group minerals are identified merely by colour.
Editorial qualification
Do not attribute the word to Werner: classical/early English uses predate him. Specific Werner dating conflicts in authoritative retrospective sources (OED 1789 vs 1911 Britannica 1798).
Related names
Sources
- Mindat: Chlorite Group — Name origin and classification
- Murray et al., New English Dictionary, chlorite (historical usage) — Historical lexical citations and conflicting dates for Werner
- Encyclopaedia Britannica (1911), chlorite — Historical mineralological classification and alternative Werner date