Using This Site

Using This Site


There are currently around 4,000 officially recognized mineral species known to occur globally – of these 365 have been confirmed from Wales, with a further 50 or so listed in the literature but which have never been properly confirmed. This site provides a comprehensive and authoritative listing of all known mineral species from Wales. By knowing what we have, we can value and conserve our geological heritage.

This site consists of two main parts, the main mineral entries (see Mineral Database) and pages that provide background information. This gives both a brief history of the science of mineralogy in Wales up to the present day, and also provides geological details as to the way in which minerals occur and are associated with each other. This will assist with an explanation of some of the more technical terms used in the mineral entries. If you have any comments or queries about any of the content please use the Feedback link to get in touch with Amgueddfa Cymru - National Museum Wales staff.


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Amgueddfa Cymru - National Museum Wales copyrighted images may be used for educational purposes provided they are for personal or school use. For all other usage please contact us using the ‘Contacts’ page. You may not reproduce images where copyright is not held by Amgueddfa Cymru - National Museum Wales, unless you have obtained the permission of the copyright holder.

A Guide to the Mineral Data

The mineral data can be accessed through an alphabetical list of mineral names. Navigation is by a simple A-Z system. Information may also be retrieved by the

. facility. The data within each entry are split into the following categories.
Mineral Name This is the CNMNC – IMA approved spelling (see page below for details of the CNMNC)
Status in Wales Categories
Confirmed occurrence
Confirmed – type locality in Wales
Confirmed - 1st UK recording
Confirmed - 2nd UK recording
Confirmed - 3rd UK recording
Discredited/obsolete mineral name
Distribution A rough estimate of the abundance of the mineral in Wales e.g.
Locally abundant
Chemical composition A general description of the chemical composition
Chemical formula The chemical formula as cited by the IMA
Chemical group The broad chemical grouping to which the mineral belongs (e.g. silicates, sulphides).
Verification This is the method by which the identification has been confirmed. The main methods listed are :
  • DTA – differential thermal analysis
  • EMPA - electron microprobe analysis (also referred to as EPMA in some text)
  • Microscope - (polarizing, reflected light or binocular)
  • IR -infra red analysis
  • SEM - scanning electron microscope
  • SEM-EDX - scanning electron microscope with energy dispersive X-ray analysis
  • SEM-WDX - scanning electron microscope with wave length dispersive X-ray analysis
  • Visual
  • Wet Chemistry
  • XRD - X-ray diffraction analysis
Localities The key occurrences of the minerals are listed here. This is not a comprehensive list but includes the best or most representative examples
Introduction An overview of the composition and occurrence of the mineral
Occurrence in Wales More specific information on the occurrence of this mineral in Wales
Geological context A guide to the geological setting in which the mineral is found. Some minerals may be present in many settings ( e.g. pyrite) whereas others are restricted to just one (e.g. glaucophane). These settings only relate to Wales. Further details of each setting are provided under ‘ Minerals where and why they occur’ .
Crystal system Minerals can be allocated to seven crystal systems, cubic, tetragonal, trigonal, hexagonal, orthorhombic, triclinic, monoclinic. Where there is uncertainty, some minerals may have more than one system listed, and others may be listed as amorphous, where the crystal system has not been determined.
References Reference to published information in scientific journals, books and magazines.