I've been working lately in various t-shirt designs for a friend who is an avid climber and also do bouldering. So is obvious that there should be rocks and boulders in the designs. I finished this one a couple of days ago:
First the rock was like this:
Which was not bad, but I wanted to make a little more interesting the shapes and lines and decided to change it as it is in the first image.
Rocks have certain qualities that make them fun and easy to draw and sketch, which is great for building up confidence, control, line-weight and line-fluidity for beginners as for not-so-newbies.
I personally like very much to draw and sketch stones and rocks because:
Perspective in rocks is not heavy (I'm not saying there's absolutely no perspective, there's always perspective in everything we draw) meaning is easy to handle and not very explicit in most of them.
There are rocks that have very sexy shapes, if one can learn to see the patterns in this shapes, it becomes easier to build a visual library when sketching rocks.
If you draw a rock not exactly as it is in real life, you can get away with it because rocks' features are very random. So it's easy to relax and draw inaccurately... it will look like a rock no matter the grade of likeness that you depict it with.
The cracks and fractures of rocks are very dynamic, diverse and fluid, they can teach your hand to have a solid but flexible flow when drawing.
Because rocks are composed of lots of different planes (unless heavily eroded) they're great for practicing shading.
Here are some studies and sketches I've done with ink and paper.
So.. rocks are cool and easy to draw. Just try them!