Introducing Langkawi’s Geo-diversity – Rock Reference Sheet Hand Specimen Close up Hand Specimen Close up

Breccia - Clastic sedimentary rock that is composed of large (>2mm diameter) angular fragments.

Conglomerate - Clastic sedimentary rock that is composed of large (>2mm diameter) rounded fragments.

Hand Specimen Close up Hand Specimen Close up

Sandstone - sand-sized grains cemented/compressed together, often with layers (bedding) – a medium-grained sedimentary rock.

Siltstone - silt-sized grains compressed together, often with fine layers (lamination) – a fine-grained sedimentary rock.

Hand Specimen Close up Hand Specimen Close up

Mudstone – clay-sized grains compressed together, often with fine layers (lamination) – a fine-grained sedimentary rock.

Coquina - limestone composed chiefly of shell fragments

Hand Specimen Close up Hand Specimen Close up

Limestone - lime grains cemented/compressed together; lime (calcium carbonate) reacts with dilute acid.

Fossiliferous Limestone - Fossiliferous Limestone is limestone that contains the remains of ancient plants or animals in the form of fossils

Hand Specimen Close up Hand Specimen Close up

Granite - a coarse-grained (clearly visible), pale-coloured, silicon-rich igneous rock

Marble - clearly visible interlocking crystals – formed when limestone is metamorphosed; the calcium carbonate crystals react with dilute acid

Dr Eric Loh 2013