Gravel is just one of those things where we know it when we see it. If someone asked us just what gravel is, we might have a hard time expressing it, but we know we see it almost daily. Gravel is everywhere, and used in everything. But gravel doesn’t come from just any old rocks; it has to come from a certain kind of gravel rock deposit and meet other qualifications to be considered gravel.
So what kind of rock is used to make gravel, and how do they effect the gravel that is used in common construction projects?
- Limestone and dolomite. These two kinds of gravel rock are usually mined together from quarries, but they don’t come out of the ground as gravel. They are blasted into fragments within the earth, and then transported to the quarry’s machinery to be crushed into the correct size. Limestone and dolomite are often found together, and so mined that way, and for gravel, it’s acceptable not to separate the two minerals from each other.
- Granite. Granite is another gravel rock that has to be crushed in order to create gravel. Granite is very hard and can’t be shaped by pressure, making it an ideal rock for roads and foundations. It’s also very attractive, so it’s nice for driveways and paths as well.
- Basalt. Basalt is a volcanic rock that comes in shades ranging from black to light gray. Because of its volcanic nature, it’s porous and light, which makes it easier than some kinds of gravel to transport. It’s an attractive stone and is often used to line gardens and walkways.
- Sandstone. Sandstone is a brown, beige, or tan rock, composed of aggregated grains of sand or rock dust. It’s a very common gravel rock in the US, and in its unbroken form is often used for buildings. One common example of that is terracotta, a popular building material in the Southwest. In its gravel form, sandstone gravel rock is used decoratively in gardens and on paths and walkways. It often contains bits of quartz, which makes it sparkle, or iron oxide, which makes it appear pink or red.
- Crimson stone. Crimson stone gravel occurs naturally in the southwestern United States. This type of mixed-color gravel rock often includes reds, blacks, pale inks, and beiges. Because of this colorful mix, this kind crimson stone gravel rock is used chiefly as decorative gravel, rather than construction gravel.
There are many different kinds of gravel rock available in the construction field, mined or made from varying sources. Whether you want to lay a new road, build a foundation, or accent a lawn or garden, one of these gravel rocks is perfect for your construction needs.