I didn't know which category to place this in but it is not quite meaningless drivel.
And Mr Ritz, the teacher, is a great academic for doing most of this a volunteer.
It all depends where you are located in Costa Rica.
A general answer is red clay, as it seems one will always find it in most areas.
There are some great deposits of volcanic soils and plenty of sandy soils near the beaches.
I have a farm in the Southwest, in the Osa district, and it is all clay after the first few centimeters of top soil.
I built a earthbag home. All together it cost $27,000 for 90 sq. meters.
It is two separate structures. Under 70 sq. meters doesn't require a building permit.
