International Rock Day

Today is International Rock Day!

The history of how this day came about is rather vague, but the goal of the day is clear: the celebration of rocks! Because, well...they rock, ha ha!

Yeah, sorry. All rocks on earth come in three main forms:
- Igneous: These rocks started out as molten magma and are formed when it cools. Naturally, you mostly find these around volcanoes. Granite is an igneous rock, for example. It's comprised of magma with a high silica content.
- Sedimentary: These rocks are formed by sediments (like minerals or organic matter) basically being cemented together thanks to the effects of erosion. Sedimentary rock covers over 70% of the Earth's land mass, but it only comprises a small amount of the Earth's crust. It's basically a covering. One example of sedimentary rock is sandstone, which is rock formed, naturally, from sand.
- Metamorphic: Metamorphic rock is formed when a rock is changed into a new form thanks to heat and pressure, hence the name. Igneous and sedimentary rocks can be changed into metamorphic rocks. Marble is an example of metamorphic rock, formed when limestone (a sedimentary rock), undergoes the metamorphic process.

Rocks are also rather important to human development. It's believed that humans and earlier hominids started making tools from rocks in the Lower Paleolithic Era. Stone tools found near Lake Turkana in Kenya from 2011 to 2014 have been dated to be about 3.3 million years old. As time went on, these stone tools would evolve further, until the development of metallurgy caused rock tools and weapons to be superseded by metals like bronze and copper.

So, yeah. Rocks are pretty darn neat. Check out some today! Thanks for reading this blog entry! See you next time!