copperas: meaning, definition, pronunciation and examples
Very LowTechnical/Historical
Quick answer
What does “copperas” mean?
A hydrated iron(II) sulfate mineral, historically produced by the oxidation of pyrite, used as a mordant in dyeing and for making inks and pigments.
Audio
Pronunciation
Definition
Meaning and Definition
A hydrated iron(II) sulfate mineral, historically produced by the oxidation of pyrite, used as a mordant in dyeing and for making inks and pigments.
The term historically referred broadly to various vitriols (hydrated sulfates of metals like iron or copper) used in industrial and alchemical processes. In modern chemistry, it specifically denotes ferrous sulfate heptahydrate (FeSO₄·7H₂O).
Dialectal Variation
British vs American Usage
Differences
No significant regional difference in meaning or usage. The term is equally archaic/technical in both varieties.
Connotations
Carries connotations of pre-modern chemistry, alchemy, traditional crafts (dyeing, tanning, ink-making), and early industrial processes.
Frequency
Extremely rare in both dialects. Slightly more likely to appear in British historical texts due to the UK's long industrial history, but the difference is negligible.
Grammar
How to Use “copperas” in a Sentence
N/A - Primarily a noun referring to a substance.Vocabulary
Collocations
Examples
Examples of “copperas” in a Sentence
verb
British English
- N/A
American English
- N/A
adverb
British English
- N/A
American English
- N/A
adjective
British English
- The copperas residue stained the stonework green.
- They followed the old copperas recipe.
American English
- The copperas deposits were mined near the spring.
- A copperas solution was the first step.
Usage
Meaning in Context
Business
N/A (obsolete industrial commodity)
Academic
Used in historical studies of chemistry, industry, textiles, or archaeology.
Everyday
Virtually never used.
Technical
Used in historical context in chemistry, metallurgy, conservation (for iron gall ink), and dyeing.
Vocabulary
Synonyms of “copperas”
Strong
Neutral
Weak
Vocabulary
Antonyms of “copperas”
Watch out
Common Mistakes When Using “copperas”
- Confusing it with copper sulfate (blue vitriol).
- Using it as a general term for modern industrial chemicals.
- Attempting to use it in contemporary conversation.
FAQ
Frequently Asked Questions
No. Despite the name, copperas is primarily iron sulfate, not a copper compound. The name likely arose because it was often found in association with copper ore deposits.
You are most likely to encounter it in historical novels, academic papers on the history of science/industry, old recipes for ink or dye, or in the context of conserving old documents (which used iron gall ink made from copperas).
Yes, but it is sold under its modern chemical names: ferrous sulfate or iron(II) sulfate heptahydrate. It is used in gardening (as an iron supplement and moss killer), water treatment, and by craftspeople making historical inks.
No. It is considered an archaic or trivial name. The correct IUPAC name is iron(II) sulfate heptahydrate, or the common name ferrous sulfate.
A hydrated iron(II) sulfate mineral, historically produced by the oxidation of pyrite, used as a mordant in dyeing and for making inks and pigments.
Copperas is usually technical/historical in register.
Copperas: in British English it is pronounced /ˈkɒpərəs/, and in American English it is pronounced /ˈkɑːpərəs/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “N/A”
Learning
Memory Aids
Mnemonic
Think of COPPER + AS: Historically, the greenish substance was associated with copper mines, though it's actually iron sulfate. "The copper mines had (AS) a green residue called copperas."
Conceptual Metaphor
N/A (Concrete substance).
Practice
Quiz
What is 'copperas' in modern chemical terminology?