Quartzite Karst Caves

Quartzite is a sort of sandstone, and like all sandstones it consists of grains of rock, the sand and a sort of glue which glues them together. In the case of quartzites it all consists almost completely of quartz or silica (SiO2). It is formed either directly as a clastic sediment, or sandstone with a high quartz content may become quartzite during metamorphism, because the other materials are dissolved under temperature and pressure and are thus removed. It typically has a low porosity.

Quartz is probably the most resistant material in the crust, not soluble by most acids, so resistant we use it to make glas which is used for chemical factories, because it is so inert. Unfortunately it is rather brittle. But sandstone is far less brittle, because of its inner structure. A grain of sand might break, but its not that sure that the force will be big enough to break the next grain, or the cement between the grains. As a result quartzite, not pure quartz, is the most durable rock known.

That's pretty bad for the formation of caves, though. What we need for caves is a material which can be removed, and that requires dissolution or at least some kind of weathering.

The Longest Quartzite Karst Caves

Cave Name Country State Length VR
Cueva Ojos de Cristal Venezuela Roraima 16,100m 73m
Cueva Muchimuk-Colibri Venezuela Churi 8,000m 160m
Cueva Charles Brewer Venezuela Churi 7,300m 110m
CaveGruta do Centenário Brazil Minas Gerais 4,700m 481m
Gruta das Torras Brazil Bahia 3,800m 0m
Gruta da Bocaina Brazil Inficionado 3,200m 404m
Cueva Juliana Venezuela Churi 3,000m 45m
Sima Auyan-tepuy Noroeste Venezuela Auyantepuy 2,900m 370m
Gruta das Bromelias Brazil Conceição do Ibitipoca (MG) 2,700m 0m
Cueva Zuma Venezuela Churi 2,500m 90m
Cueva de la Arana Venezuela Churi 2,500m 0m