Quartzite

Composed of quartzite covered with a softer syenite sheath, it was intruded about 1.5 billion years ago.

Bornhardts are commonly composed of igneous rocks, often granites, but examples of gneiss, quartzite and arkose bornhardts exist.

Formation of graywacke-argillite-conglomerate, the Drake Icefall Formation of black shales and marble, the Conglomerate Ridge Formation of conglomerate and quartzite, the Liberty Hills-Springer Peak-Frazier Ridge Formations of quartzite-argillite, and the Minaret Formation of

The rocks of the Guiana Shield consist of metasediments and metavolcanics (greenstones) overlain by sub-horizontal layers of sandstones, quartzites, shales and conglomerates intruded by sills of younger mafic intrusives such as gabbros.

The archipelago consists predominantly of pre-Tertiary continental islands primarily of quartzites and shales covered by basaltic lava.

The valley is situated between the Silurian Shawangunk quartz conglomerate and the lower Cambrian Hardyston quartzite.

These rocks are largely igneous in origin, mixed with metamorphosed marble, quartzite and mica schist and intruded by later basaltic dykes and granite magma.

In general, the geology of the Sierra Nevada del Cocuy consists on sedimentary rocks from the Cretaceous, broadly made up of sequences of quartzites, sandstones and fine-grained mudstones of Aptian and Cenomanian ages.

The Tonquin Valley, which cradles Amethyst Lakes, runs roughly north-south, parallel to the 1,000-metre (3,300 ft) Precambrian quartzite wall of the Ramparts, part of the South Jasper Range.

Basalt, Quartzite