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Sandstone

Sandstone is a very fascinating rock that I first met when I was 18. Being born and raised in Cincinnati, Ohio, I was only familiar with the coarse limestone and shale that made up the bedrock around town. My family didn't travel much, so I was fairly sheltered. But all that changed in the summer of 1971 when I went on a planned three-week driving tour of the Southwest. Sandstone rock out there is as plentiful and exposed as biceps and buttocks on a sunny Florida beach during spring break. My favorite Arizona sandstone was the Coconino sandstone. You can see its gleaming vertical faces in the Grand Canyon.

When it comes to naming something, sandstone really describes what it is. My college degree is in geology, so I can vouch that there are rock names that simply don't make sense. Sandstone is not one of those. Imagine taking billions of pieces of sand and packing them tightly together. That's what sandstone is in its most basic configuration.

The hardness, density and durability of sandstone are directly related to the type of sand that makes up the matrix of material in the rock. Realize that sand is simply small rock particles, and that there are many different types of rock!

If you want to be amazed one day, take a quarter teaspoon of sand and hold it in your hand. There's a great chance you'll see tiny red, white, black, gray, and maybe green grains of sand. They may be different sizes as well. It's best to do this with sand from a gravel pit or on a beach near a sizable river. If you do this on some ocean beaches, the sand there may be just ground up shells.

Sandstone comes in different colors. At Zion and Grand Canyon National Parks, you can see a wide variety of colors from red sandstone to buff and even white sandstone. Black sandstone, as well as brown sandstone, is common. Some of the colors come from chemical interactions as the sand is transformed into rock. This happens over millions of years, and can be influenced by high pressures, temperatures and mineralized waters that saturate the sand as it's cooking under thousands of feet of sediments.

Limestone sandstone is a misleading description. It's sometimes common to see limestone and sandstone as nearby rock formations. In fact, a geologic rock formation of limestone can transition into a sandstone formation! To see that happening in real time, all you have to do is visit a clear ocean environment where a coral reef is adjacent to a clear-water river that's depositing sand as it flows into the ocean. You've got limestone being created by the reef, while a mile or so away the mouth of the river is creating sandstone. Geology is so cool when you stop and think about it.

Sandstone rocks can be very hard and durable. Imagine sandstone where the sand grains are nearly all quartz. Quartz is a very hard rock and is a primary component of granite. You surely know that granite is a hard rock, so imagine a rock made up of nearly 100 percent quartz! There are sandstones out there like this. A sandstone building in your city or town may be made from this material.

As with many other rocks, sandstone can be cut into large blocks in a quarry. After a single sandstone block is raised from the quarry, it can then be cut into many sandstone materials ranging from small sandstone coasters all the way to large sandstone tiles. Building stone sizes can range from brick size to massive blocks that measure feet wide and tall and many inches thick. It all depends upon the scale of the building and what the architect is trying to accomplish with his design.

The next time you have some building project that involves natural stone, stop by a stone center that has all types of rock. Take a look at the different sandstones. They make great retaining wall blocks, stepping stones in a garden path and a formal fireplace for that matter. You'll be amazed at all the different types of natural sandstone that you'll see. Try to purchase one that has high quartz content if you want the stone to last nearly forever!

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