What to look for in rocks for your collection

Author: jangkrikjr

25 Jul

Rock collecting is a relatively easy hobby. That’s what some people might think. However, there are different aspects of collecting rocks that is quite challenging which makes the whole rock hunting thing actually quite exciting. You see, rocks have unique characteristics and looking for a good rock sample can be very challenging. You will have to study hard to know what to look for in rocks for your collection.

Maybe, one of the first things that you need to differentiate is between a rock and a mineral. A mineral, like quartz and calcite, have unique structures and composition. A rock, however, is made up of two or more minerals which have been combined together through pressure or heat.

Other important things that you will look closely into are the presence of crystals in your rocks. These crystals are the flat and often shiny objects found on the surfaces of the rocks. The presence of fossils is something that might be interesting as well. There are times when leaves, shells, insects or animals become fossilized. They leave behind imprints which could be a source of history of the place.

Other key characteristics include gas bubbles which are basically air pockets which appeared when the rocks were being formed. The resulting rock will have holes on it making it appear like a gray Swiss cheese. A glassy surface is also a characteristic of a kind of rock and you should learn to look for it. Ribbon-like layers or wavy stripes of different colors is a unique characteristic and is a good thing to for in a rock sample.

The characteristics of the rocks mentioned above will help you identify which rocks falls under which type. There are basically three general groupings of rocks. These are igneous, sedimentary and metamorphic. Examples sedimentary include conglomerate and limestone while metamorphic rocks include gneiss and marble. On the other hand, basalt and obsidian fall under the igneous rock type.

By looking closely at the texture of your rock samples, you can identify which rock type it falls under. When you find a porous or smooth rock, try pouring vinegar on a sample. It if sizzles than you might have either a limestone (sedimentary rock) or a marble (metamorphic) in your hands.

By knowing how each rock type is formed, you will have more or less an idea of the rocks that you have found in your collection so far. So if you found rocks near a riverbed, there’s a big chance that it is a kind of sedimentary one since these kinds of rocks form from the layering and solidification of matter like clay, small rocks, etc. Knowing what to look for in rocks would help you greatly in coming up with a great collection.

Share and Enjoy: