All our rocks are carefully selected for educational study. They come in labelled trays. The trays are normally 3″ x 2″ size depending on the rarity of the specimen. Average specimen size is shown below. These are ideal for classroom teaching and are a size that can be easily passed round the classroom for students to get a feel for each type.
Sandstone is a clastic sedimentary rock composed mainly of sand-sized silicate grains. Sandstones make up about 20 to 25 percent of all sedimentary rocks.