Loess – the Earth’s most fragile rock!

Loess Sedimentary RockLoess is formed from fine (small) grained, windblown sediment in glacier or desert areas.  Loess is made of mostly silt but may also have some small amounts of sand and clay.  The major mineral present is quartz with minor amounts of feldspar, calcite, dolomite, and clay.  Loess samples thed to be homogeneous throughout, which means that the grains are very similar in size, shape and color.  Samples of loess also tend to be very “friable.”Â  Friable is a term used for rocks that can be easily broken apart with very little pressure.  Loess will crumble if you squeeze it too hard or drop the sample.  Loess tends to be tan, pink, gray, yellow, or brown in color. 

 Loess is often deposited across very large areas and can be very thick.  Loess which is formed in desert areas are formed when wind-blown silt accumulates in large areas.  Loess which is formed in glacier areas is formed when the glaciers break down rocks into very fine grains which are then blown into deposits.  Interestingly, loess which is composed of angular grains can form banks or walls which are resistant to breaking down or slumping; however, over the years, wind and water can slowly breakdown the rock.  Deposits of loess can be found in

Russia, United States, China, Hungary, and Belgium.

Shop for loess and other individual rocks and minerals as well as kits at www.MiniMeGeology.com today!


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