Oolite

Oolite is a variety of quartz which occurs in tiny egg-shaped spherules. It is usually solid brown in color and is very similar to algae. Individual oolite spherules are about one sixteenth of an inch (one to two millimeters) which is too small to be cut. The aggregate stone is usually just polished to bring out the color and mounted in silver jewelry (particularly tiaras or pectorals). A typical specimen has a base value of 10gp.