Minerals - Where and How They Occur

Extra information on mineralogy and minerals in Wales is provided here to complement the mineral database pages. If you would like further information or have any geological or mineralogical queries please contact the Mineralogy & Petrology Section, Amgueddfa Cymru — National Museum Wales via the feedback & contact page.

Minerals occur in a wide range of geological settings. Many are found as the essential constituents of rocks: these are termed rock-forming minerals, while others are found concentrated in mineral deposits. Rocks are divided into three main categories, igneous, metamorphic and sedimentary, and each of these categories is subdivided further using internationally agreed terminology and definitions. Mineral deposits have no such single standard for classification. The Welsh mineral deposits, described in this site, have therefore been grouped into an extensive range of settings to provide a clearer picture of the geological processes that formed them.

Rock-forming minerals:

• Metamorphic Minerals
• Meteorite Minerals
• Sedimentary Minerals

Ore deposits:

• Hydrothermal Minerals
• Supergene Minerals