IGH 6 - Mineralogy Theme
Minerals are individual combinations of elements that are found as distinct forms in their own right. Several thousand individual minerals are known. Igneous rocks and metamorphic rocks are usually formed from particular associations of minerals and their classification can be based on the mineral species, of which they are made, as well as texture, bulk chemistry and other characteristics such as their mode of origin.

Minerals are therefore an important geological theme to be assessed in the Irish Geological Heritage Programme. It is necessary to protect sites with occurrences of rare minerals, or where mineral species were first identified and described from. We should identify a selection of sites that represent the range of minerals known in Ireland and the places with exceptional variations, since many common minerals can occur in different forms (or habits).

The beauty and rarity of some minerals can be a big attraction for collectors and while some sites can sustain collecting, others are so rare or of limited occurrence, that restrictions should be placed on collecting at these sites to retain some for everybody to see, rather than just a few.

Some mineral deposits will be assessed within the scope of the IGH15 Economic Geology theme, since they are bulk industrial minerals which are mined and quarried for use in the chemical industry or in everyday materials. Gypsum (Calcium sulphate) for example, used in plaster, plasterboard and cement is such a mineral, mined at Knocknacrann in County Monaghan. Common salt (halite) is mined in Northern Ireland, but is not commonly found in the Republic.

Some minerals are only found as micro minerals that are not visible to the eye, but are identified using sophisticated techniques, but the sites where they are found may still warrant protection as NHAs.