Akadama.....
Literal translation........Red Ball Soil.......
To an American this Akadama looks as "Foreign" as it really is.  It's large grained.  It's without any type of "powdery" sized stuff that we expect in our potting medium.  Yet..........this is what the Japanese use for their Bonsai.  Now.....don't shake your head and look down at your shoes......It's what their "soil" in their backyard is basically like. Certainly not like anything we're used to digging around in in our backyard.  Remember, Japan is nothing more than an old volcano.......so the soil is volcanic......no peat moss, no pine bark, etc.   This akadama is literally dug out of old Cryptomeria Forests of Japan at about 10 feet depth.  It's piled up on concrete areas to let dry, then it goes through sifters to separate the grain sizes.  It is flashed fired to remove any organic matter that may have blown on it or somehow visited it during its "curing" process.  If you're scared or apprehensive about Akadama for your Bonsai, then just try a small amount of it on one or two of them.  We assure you that you will be happy and your Bonsai will certainly feel at "home" in its soil.  Try it.......You'll like it.

For your comparison of Small, Medium and Large grain Akadama. A 25 cent coin is used for scale.