Sandstone is classified as a sedimentary rock, which can take thousands of years to form.
Sandstone contains grains between 1/16 millimeter and 2 mm in size (siltstone is made of even finer grains). Therefore sandstone doesn’t signify any particular mineral, but in practice, sandstone is usually almost all quartz.
However, most sandstone has a small amount of other minerals—clays, hematite, ilmenite, feldspar, and mica. These minerals add color and character to the quartz matrix.
Sandstone forms when sand is lays on the surface and is eventually buried by more sand or other materials. Usually this happens offshore near river deltas; however, desert dunes and beaches create sandstone beds too.
This type of rock does not usually contain good fossils, because the energetic environments where sand beds form do not have the necessary stability needed.
The most common materials in sand — US inland continental settings and non-tropical coastal settings — is silica (silicon dioxide, or SiO2), usually in the form of quartz. This rock material’s chemical inertness and considerable hardness is resistant to weathering.
Making Your Own Sandstone
Student Materials (per group)
Dry sand ((found at home improvement stores)
Ground up sandstone
Cementing solution (2 parts water and 1 part Epsom salts)
2 Paper cups
- Pieces of sandstone rocks for student comparison
- Ground up pieces of sandstone rock for student comparison
- Digital cameras
- Take pictures using the digital camera of every step of the sandstone making process
- Pour some sand and ground up sandstone rock on a paper towel and exam with a magnifying glass
- Record your observations of the sand
- Fill a paper cup half full of sand
- Add the cementing solution until it covers the sand completely
- Pour the sand and cementing solution back and forth between the second until thoroughly mixed
- Place the cup with the mixed solution in a warm place and let it sit there overnight
- Next day, remove the wet sandstone from the cup gently and place on paper towels for 2 days
- Make observations of your sandstone with sandstone rock provided by the teacher.
- Prepare a multimedia presentation of your investigation
- Ask students to compare the differences and similarities between sandstone they made with the sandstone rocks you provide.
- Refer to 20 questions to ask students in science projects for suggestions for other kinds of questions to ask students.