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Fact sheet


Stibnite (antimony sulphide) is the main ore mineral of the metal antimony.

Small amounts of antimony minerals were found in many Cornish mines but only a few were worked for antimony. Fewer still tried to produce it as their single main product.  Most of these mines were in the north of the county. This specimen was acquired by the Royal Institution of Cornwall before 1881. It is from Wheal Boys (also called Trewetha Mine), an old antimony mine in the parish of St Endellion, which was worked in the late 18th century.

Antimony is most useful when alloyed with other metals, increasing their strength and durability. It was added to some types of pewter (an alloy of tin) from the late 17th century onwards.

Chemical Formula: Sb2S3

Specimen no. TRURI: 801.1578
Location: Wheal Boys
Grid Reference: SX 004 800


Additional images
  • Stibnite 5 cm across
  • Stibnite 22 cm across
  • Stibnite 22 cm across
  • Stibnite 5 cm across
  • Stibnite 5 cm across
50.585144, -4.819264
About this collection

This Collection focuses on Cornwall and West Devon’s mineralogical and mining heritage.  The specimens it features are drawn from the collection of the Royal Institution of Cornwall (RIC) held at the Royal Cornwall Museum (RCM). 

This collaborative project involving the RCM, the Cornish Mining World Heritage Site and The Open University explores how access to the RIC’s mineral collection and the stories it can tell can be widened using digital technology.  It includes radioactive minerals from Cornwall that would otherwise be inaccessible to the public for health and safety reasons.

Sample details

Category guide  
Category Guide
Refers to any word or phrase that appears in the individual rock names. Names are generally descriptive; they allow users to search for broad terms like ‘granite’ as well as more specific names such as ‘breccia’. However, the adjacent descriptions of the specimens captures a wider range of general words and phrases and is a more powerful search tool.
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Accessory minerals
Minerals that occur in very low abundance in a rock. They are usually not visible with the naked eye and contribute perhapssver, they often dominate the rare elements such as platinum group metals.
Rock-forming minerals
Minerals that make up the bulk of all rock samples and are also the ones used in rock classi?cation.
Selecting one or more period, for example 'Jurassic'.
A term used to group together related samples that are not already gathered into a single Collection. For instance, there is a ‘SW England granites’ theme that includes such rock types as granite, hydrothermal breccia, skarn and vein samples.
A general term used to label a rock sample. It is a useful way of grouping similar samples throughout a collection. Category names are often, but not exclusively, common rock names (e.g. granite, basalt, dolerite, gabbro, greisen, skarn, gneiss, amphibolite, limestone, sandstone).
The owner of the sample that appears in the collection. For example, NASA owns all the samples that appear in the Moon Rocks collection
We would like to thank the following for the use of this sample: