Inside: Weathered rocks and seashells make up beach sand. Using sand science you can investigate unique properties of Great Lakes sand.
How Beach Sand is Formed
What is beach sand made of? Most of us can guess how sand forms. It comes from rocks broken up by waves and winds and other forces of nature. Bashed together by waves, rocks turn into smaller fragments over time until they become the tiny granular material we love to walk along on a warm summer’s day, create sand castles with during a fabulous day at the beach or get buried in by your friends.
From a science standpoint, sand has a more particular composition. However, the origin of sand depends upon the geography of the area. Most beaches in the world share common elements but each area has its own sand composition that gives it unique characteristics. Caribbean sand is uniquely white. This is because a large part of the sand is made up of coral and shell remains. The areas in North America that surround the Great Lakes also boast some exceptionally beautiful, sandy freshwater beaches.
What is Beach Sand? Composition of Great Lakes Beaches
Great Lakes beaches are made up of beautiful tan-colored sand. Click To Tweet Over 90% is silica, a pure form of quartz, useful in making glass. In fact, sand hit by lightning can form some amazing glass sculptures.
Feldspar is a common mineral in the Great Lakes area that dissolves into the clay. Waves wash out the clay leaving pink or grey flecks of feldspar to color the sand. A handful of Lake Huron sand has the following composition:
- 87-94% quartz
- 10-18% feldspar
- 1-3% magnetite
- less than 1% of the following: garnet (red), calcite (white), ilmenite (brownish-black), hornblende (green, brown-black), epidote(yellowish-green, brown-black)
Great Lakes beaches can be a colorful mixture of grains if you look closely. The most interesting mineral in beach sand has to be magnetite. Click To Tweet I often see streaks of black in the beaches I visit around Sarnia. I have seen these streaks for years and I mistook them for oil released by ships and boats common along the Great Lakes. Although I am sure there is traces of engine oil and car oil present in the Great Lakes, these black streaks are not from oil pollution.
Magnetite in Beach Sand
Summer waves pile sand on to the shoreline. As the sand dries in calmer weather, wind blows away lighter particles of sand forming dunes. Heavier minerals are left. By the end of summer, the heavy iron-rich magnetite accumulates creating stretches of beach with black streaks. The neat thing about magnetite is its magnetic properties. Pass a magnet closely over Great Lakes Beach sand and you’ll find black grains of magnetite attached to the magnet.
Magnetism and Beach Sand:Easy Experiment
If you loved this activity, try this to investigate why wet sand looks drier when you step on it.