Sand is formed from the breakdown of rocks and has been deposited in the soil as silicon particles. Sandy soils are gritty to the touch, loosely packed, and very porous. The second layer of the solution will be the silt, this layer will be dark in color. Silt is the product from the breakdown of the rock found in the area and has the same chemical properties of the local rock. Silt when dry has the feel of powdery and when wet it feels slippery.
Silt adds bulk to the soil, supplies minerals through chemical breakdown, and helps retain water.
The third layer of the solution will be the clay, this layer will again be light in color and have a sheen to the surface. Clay is also formed from the breakdown of rocks but it has gone through chemical changes that have altered it properties. Clay is the primary source of nutrients for the plants and for storage of long term water. Clay is the primary source for nutrients because clay carries a negative electrical charge while most of the beneficial nutrients for the plant carry a positive electrical charge. This allows clay to hold these nutrients on their surface ready for the plant to liberate them for their use.