Logging Tasks
Answers to the following to be sent prior to logging. Don't wait for my approval before logging. Most importantly, have fun learning and don't worry about getting the answers right.
- Pick any floor tile that you think has the best Liesegang Rings. Describe the colours and grain size of the tile. What kind of stone do you think this is?
- What colour are the rings? What mineral has stained the stone?
- Based on the curvature of the rings, give an estimate of the size of the rings.
Take a walk at Westminster
The pavement here has a funny colour - its half gray and half rust, with noticable curves. These are Liesegang Rings.
Limestone is a sedimentary rock, meaning it is formed layer by layer as the main components, usually calcite or aragonite that are crystal forms of calcium carbonate (CaCO3) deposits over millions of years and eventually cements together. Calcium carbonate is also the main component of pearls and shells from clams, snails and even eggs. It's formation in marine environments means that it often contains bedding planes and a variety of fossils.
Sandstone is a sedimentary rock, it can be found in many colours including; grey, brown, red and yellow,. You will often be able to identify bedding planes which run all the way through the rock. (Although not all sandstones show visible bedding planes and it is not always possible to identify bedding planes if they are deeper beds of rock). The rock will be quite durable but feel rough to the touch and small grains will come off when you rub it vigorously. Sandstone is usually very porous.
The rust colour you can see here comes from iron rich chemicals seeping into pores of sedimentary rocks, and through a chemical reaction-diffusion process, the minerals precipitate in a pattern fue to supersaturation and nucleation effects.
