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Rhyolite is a volcanic, igneous rock which is relatively common. It is a rather intrusive rock with an extremely high content of silica SiO2. it is remarkably similar to the common granite but differs from the granite in many ways. Rhyolite tends to contain crystals, which are extremely small and microscopic in size, meaning they cannot easily be seen with the naked eye. Visually, rhyolite appears very similar to granite, but the granite crystal size is considerably larger. This tiny crystal within the rock is due solely to the rapid cooling of the rhyolite lava during formation, it is a common geological knowledge that the rate of cooling of magma is indirectly proportional to the size of the crystal so implicatively this mean that the faster the cooling, the smaller the crystal, and the slower the cooling, the greater the crystal. Rhyolites are found ultimately in volcanic arcs.

The name Rhyolite was first adopted to science and geology by a German geologist by the name Ferdinand Von Ritchofen. It is also fondly referred to as felsic rock and was first explored by Ritchofen during his explorations in the Rocky Mountains in the year 1860. Rhyolite are known to be chemically acidic and constitutes the minerals, quartz, feldspar plagioclase and alkali.

The structural tendencies of a rhyolite are particularly compelling, it is widely similar to that of granite. The difference being, the grain sizes are smaller and it is solely crystalized from silicate at an exceedingly minute temperature. It is constituted of bright coloured silicates and mainly appears in pinkish colour with an occasionally gray colour known to be available. Texturally, this ranges from aphantic i.e. finely grained, to glassy or even porphyritic, but generally is of an aphantic texture. Rhyolite, as mentioned before, has a remarkably high content of silica and low contents of magnesium and iron. When a rhyolite melts it produces an exceptionally turbulent lava which flows viciously.

Rhyolites can occur in some variable forms which are distinguishable from each other by the size of crystal within it. If there is remarkably rapid cooling of the rhyolite lava in such a way that no crystal is formed, then it is better known as an obsidian. If the rock contains a constituency of holes or vesicles, it is then properly referred to as pumice. Other than these two forms, a rhyolite contains small sized crystals.

Rhyolite is a tremendously useful rocks in general. Due to the fact that it is usually found with frozen flow bands within the rocks structure it is mainly used as decorative stones i.e. it is used extensively to decorate walls and monumental statues due to its bright colours. It is also used as scouring stones that are used to clean the surface of things or to smoothen out roughen edges of other stone, then it also used as abrasive that are used to shape and smoothen materials especially minerals also used as an ornamental stone used to make ornaments for fashion designing.

Additional Resources

Rapakivi   Sandstone   Sandstone Uses

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