THE GEMHOOD EDITORIAL LIBRARY
Bournonite gemstone guide
Bournonite: mineral identification, origin, colour, Mohs hardness 2.5–3, collector safety and care.
Gem facts · Quality considerations · Care & meaning
A study in colour and character
Every shade has a story.
Typical appearances for Bournonite. Natural stones vary, and lighting or treatment can change their appearance.
Where Bournonite is found
France; United Kingdom; Bolivia; Peru; China
France
United Kingdom
Bolivia
Peru
China
How it forms
Crystallises in hydrothermal sulphide veins, often with galena, sphalerite, pyrite and quartz.
These are representative geological or commercial sources, not certified provenance for an individual stone. Country of origin should be substantiated independently when relevant to value.
01 / THE GEM AT A GLANCE
What is Bournonite?
Bournonite is a lead-copper-antimony sulphosalt. Its reported composition is PbCuSbS₃; Mohs hardness is 2.5–3. Typical colour: Steel-grey to iron-black, metallic. Crystallises in hydrothermal sulphide veins, often with galena, sphalerite, pyrite and quartz. Metallic blocky or short prismatic crystals; repeatedly twinned specimens may form toothed or cogwheel-like patterns.
Composition: PbCuSbS₃. Scientific properties apply to the mineral or gem type, not as a guarantee about an untested individual product.
Bournonite is a lead-copper-antimony sulphosalt. Its reported composition is PbCuSbS₃; Mohs hardness is 2.5–3. Typical colour: Steel-grey to iron-black, metallic. Crystallises in hydrothermal sulphide veins, often with galena, sphalerite, pyrite and quartz. Metallic blocky or short prismatic crystals; repeatedly twinned specimens may form toothed or cogwheel-like patterns. Characteristic appearance: Metallic blocky or short prismatic crystals; repeatedly twinned specimens may form toothed or cogwheel-like patterns. Representative reported localities include France; United Kingdom; Bolivia; Peru; China. Those regions are reference occurrences, not independently verified origins of products offered for sale. Look for cogwheel-like twinned faces but do not treat shape as definitive; compare associated minerals and specimen source. Mineral colour and a catalogue photo cannot authenticate an item; serious purchasing decisions require reliable identification, treatment disclosure and specimen provenance. Collector display specimen only; low hardness and toxic-element content make it inappropriate for wearable or handling-intensive uses. Store in a labelled enclosed display case; do not polish, grind, soak or allow children to handle. Contains lead and antimony. Avoid dust, ingestion, mouth contact and crystal-water rituals; wash hands after handling. The famous cogwheel habit comes from contact twinning and is one of the most useful visual clues in good collector crystals. Collecting note: review a specimen in daylight and neutral light where practical; ask for dimensions, weight, original label, exact source and documented history. Specimen photographs show individual examples, not the full range of natural appearances. Mineral names, historical trade synonyms and rock names should be verified before buying. When uncertain, consult an accredited gemmologist or a mineralogical laboratory rather than applying scratch, flame or acid tests to a valued piece.
02 / LOOK CLOSER
Colour, appearance and quality
Characteristic appearance: Metallic blocky or short prismatic crystals; repeatedly twinned specimens may form toothed or cogwheel-like patterns. Representative reported localities include France; United Kingdom; Bolivia; Peru; China. Those regions are reference occurrences, not independently verified origins of products offered for sale.
Before you choose a stone
Compare images taken in more than one lighting condition, ask for views of the actual item and check how the cut and setting change its appearance. A gemstone type is not a standard grade: each natural specimen has its own colour, inclusions and workmanship.
THE GEMHOOD BUYER'S FIELD NOTES
How to choose Bournonite: three checks
- 01
Look for cogwheel-like twinned faces but do not treat shape as definitive; compare associated minerals and specimen source. Mineral colour and a catalogue photo cannot authenticate an item; serious purchasing decisions require reliable identification, treatment disclosure and specimen provenance.
- 02
Store in a labelled enclosed display case; do not polish, grind, soak or allow children to handle.
Contains lead and antimony. Avoid dust, ingestion, mouth contact and crystal-water rituals; wash hands after handling.
Collector display specimen only; low hardness and toxic-element content make it inappropriate for wearable or handling-intensive uses.
These notes describe typical gem material and trade practices. They do not independently grade or identify a specific item offered for sale.
03 / BUY WITH CONFIDENCE
Natural, laboratory-grown, treated or imitation?
Look for cogwheel-like twinned faces but do not treat shape as definitive; compare associated minerals and specimen source. Mineral colour and a catalogue photo cannot authenticate an item; serious purchasing decisions require reliable identification, treatment disclosure and specimen provenance.
These distinctions should be clear in the listing for any particular gem. Treatments are not automatically unacceptable, but an undisclosed treatment, vague mineral identity or unsupported origin claim prevents an informed purchase. Where material identity materially affects value, an independent gemological identification report may be worth considering.
A CLOSER LOOK
Formation, structure and chemistry
Crystallises in hydrothermal sulphide veins, often with galena, sphalerite, pyrite and quartz.
This lead-copper-antimony sulphosalt is described by PbCuSbS₃. Its Mohs hardness is 2.5–3; that number measures resistance to scratching, not toughness or the safety of a crystal in use.
A CLOSER LOOK
What a genuine specimen can look like
Metallic blocky or short prismatic crystals; repeatedly twinned specimens may form toothed or cogwheel-like patterns.
Typical colours include Steel-grey to iron-black, metallic. Crystal habit and associated matrix give useful clues, but appearance alone cannot establish a mineral species.
A CLOSER LOOK
Identification and common confusion
Look for cogwheel-like twinned faces but do not treat shape as definitive; compare associated minerals and specimen source.
Compare it carefully with acanthite, sphalerite. Ask for a documented locality and independent testing before accepting a valuable specimen identification.
A CLOSER LOOK
Where specimens are reported
Reference occurrences include France; United Kingdom; Bolivia; Peru; China.
These places are examples of recorded occurrences, not country-of-origin claims for jewellery or loose specimens sold by GemHood.
A CLOSER LOOK
Jewellery, collecting and fair purchase
Collector display specimen only; low hardness and toxic-element content make it inappropriate for wearable or handling-intensive uses.
Contains lead and antimony. Avoid dust, ingestion, mouth contact and crystal-water rituals; wash hands after handling.
Request clear seller photographs, scale measurements, evidence of damage and treatment disclosure. A historical locality or specimen label is not an independent certificate.
A CLOSER LOOK
Care, storage and handling
Store in a labelled enclosed display case; do not polish, grind, soak or allow children to handle.
The famous cogwheel habit comes from contact twinning and is one of the most useful visual clues in good collector crystals.
For sensitive or hazardous collector minerals, store them out of reach in clearly labelled enclosures; never grind, pulverise or place specimens into drinking water.
04 / WEAR IT WELL
Bournonite in jewellery
Collector display specimen only; low hardness and toxic-element content make it inappropriate for wearable or handling-intensive uses.
05 / MAKE IT LAST
How to care for Bournonite
Store in a labelled enclosed display case; do not polish, grind, soak or allow children to handle.
One essential care distinction
Mohs hardness describes resistance to scratching, not resistance to breaking. Gemstones with cleavage, existing fractures, porous surfaces or fillings can need extra care regardless of their hardness number. If you do not know whether a piece has been treated, begin with the gentlest appropriate cleaning method.
06 / CULTURE & MEANING
History, heritage and symbolism
The famous cogwheel habit comes from contact twinning and is one of the most useful visual clues in good collector crystals.
Traditional meanings and spiritual associations are part of cultural storytelling. They are not evidence that a gemstone diagnoses, prevents or treats any medical condition.
GOOD QUESTIONS, CLEAR ANSWERS
Bournonite FAQs
What is Bournonite?
Bournonite is a lead-copper-antimony sulphosalt. Its reported composition is PbCuSbS₃; Mohs hardness is 2.5–3. Typical colour: Steel-grey to iron-black, metallic. Crystallises in hydrothermal sulphide veins, often with galena, sphalerite, pyrite and quartz. Metallic blocky or short prismatic crystals; repeatedly twinned specimens may form toothed or cogwheel-like patterns.
How hard is Bournonite?
Mohs 2.5–3. Durability also depends on cleavage, brittleness, handling and the specific specimen.
What colours and crystal shapes does Bournonite have?
Steel-grey to iron-black, metallic. Metallic blocky or short prismatic crystals; repeatedly twinned specimens may form toothed or cogwheel-like patterns.
Where is Bournonite found?
France; United Kingdom; Bolivia; Peru; China. A specific seller’s location claim needs its own supporting evidence.
Can Bournonite be worn in jewellery?
Collector display specimen only; low hardness and toxic-element content make it inappropriate for wearable or handling-intensive uses.
How should Bournonite be cleaned and stored?
Store in a labelled enclosed display case; do not polish, grind, soak or allow children to handle.
How can I tell whether Bournonite is genuine?
Look for cogwheel-like twinned faces but do not treat shape as definitive; compare associated minerals and specimen source. Mineral colour and a catalogue photo cannot authenticate an item; serious purchasing decisions require reliable identification, treatment disclosure and specimen provenance.
Are there handling or treatment concerns for Bournonite?
Contains lead and antimony. Avoid dust, ingestion, mouth contact and crystal-water rituals; wash hands after handling.
A NOTE FROM THE GEMHOOD EDITORIAL DESK
How to use this guide
We explain gemstone properties, known mining regions and customary treatments to help you shop more confidently. Each gemstone can vary in quality and individual provenance, so compare the actual jewellery listing and request supporting documentation if origin, treatment or natural-versus-laboratory-grown status affects your choice.
Our gemstone library is educational and does not act as a laboratory identification certificate. Independent gemological assessment is advisable for valuable or disputed claims.
EDITORIAL REFERENCES
Research and further reading
References describe mineral species and representative occurrences, not verification of any individual item for sale.
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Compare Bournonite with similar gemstones
These stones can overlap in colour, appearance or jewellery use. The mineral identity, treatments and durability may be very different.
KEEP EXPLORING
Other gemstones to discover
Educational articles describe gemstone types and common trade practices. They are not individual gemological certificates, current price appraisals or medical advice.