Rock Types

Toolmark on Bromsgrove Sandstone Formation blocks, Hartlebury Castle
Sandstone is a sedimentary rock made up of cemented sand sized grains of minerals. The most common constituent is quartz, followed by the mineral feldspar. Sandstones are the most common building materials in Herefordshire and Worcestershire and so make up a large number of buildings.
Photomicrograph of Bath Stone oolitic limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3). Most limestone is composed of skeletal fragments of marine organisms such as coral, forams and molluscs.
Close-up of Ludlow Shales in Bank House, Leintwardine (copyright Scenesetters)
Siltstone is a sedimentary rock with a finer grain size than sandstone. Individual grains are at the limit of what is visible with the naked eye. In several areas there is a continuum between limestone and siltstone depending on the amount of calcium carbonate in the rocks.
Block with a mafic dyke in granite
Igneous rocks are those formed by the solidification of molten magma or lava. Examples include granite, basalt and diorite.
Marble wall, Ruskeala, Russia (copyright Aleksander Kaasik CC-by-SA 4.0)
Metamorphic rocks are formed by the alteration of igneous or sedimentary rocks by exposure to elevated temperatures and/or pressures. The change in conditions causes the minerals in the rock to change to new ones. Examples of metamorphic rocks include slate and marble.

Related Items

  • Malvern Stone: Lansdowne Crescent Methodist Church

    Malvern Stone

    Igneous rubble stone used in Malvern and around the Malvern Hills. A variety of lithologies make up the Malvern Hills of which diorite and tonalite (intermediate between granite and basalts) are the most common. Granites, pegmatites, dolerites, basalts and ultramfic lithologies also occur. Many of the rocks have been sheared and altered by fault movement, […]

  • Hollybush Sandstone

    Cambrian age, dark green, flaggy, micaceous sandstone with abundant chlorite and glauconite. Only known use for building is in Hollybush Church. Browse sites on the database using Hollybush Sandstone

  • Westmorland Slate

    Also known as Honnister Slate, this is variety of slate from the Borrowdale Volcanic Group of Cumbria. Unusually it is formed from a tuff (volcanic ash deposit) – erupted during the Caradoc Age of the Ordovician (458 to 448 million years ago) – which has been subjected to high pressure and heat, metamorphosing it to […]

  • Crinoids in Wenlock Limestone ("Ledbury Marble") cobble, Ledbury

    Wenlock Limestone

    Pale grey nodular or thinly bedded limestones. In character it varies markedly across the region. Examples from the Malvern Axis hills (Abberley, Suckley etc.), Ledbury and Woolhope Dome can be spectacularly fossiliferous, corresponding to reef bodies. During the Silurian water depth deepened towards open ocean to the west and around Ludlow the Wenlock limestone is […]

  • Aymestry Limestone, Gatley Park Folly, Leinthall Earls

    Aymestry Limestone

    Blue-grey, hard, nodular argillaceous limestone. The presence of the strongly ribbed brachiopod Kirkidium knightii is diagnostic for this formation. Widely used in the Mortimer Forest, Woolhope Dome, Suckley Hills and Ledbury areas. The character of the formation, like most of the Silurian strata, can vary markedly between a massive limestone suitable for dimension stone to […]