When you mention gravel, everyone has a story. Maybe it was their childhood days skinned knees and elbows from riding their home-made soap box go-cart down the hill, or in my case, the occasional “bing” across the noggin from the kid next door.
Did you ever stop and pick up a common ol’ rock and examine it? Some of the white limestone in the driveways around town has tiny little fossils imbedded in the gravel – leftovers from millions of years ago. Bethany Falls limestone, which forms the beautiful, white rock bluffs along the Missouri River, is probably one of the finest rocks in the world for mixing cement and crushed gravel. Most roads and highways across Jackson County are paved with concrete or asphalt made with this limestone.
If you drive out across the countryside in Clay, Lafayette or Johnson counties, for example, you will quickly notice limestone crushed gravel is the surface of choice along the back roads. Something else you will notice, when you get back home you will need to wash your car, because it will be covered with the white dust from the crushed limestone gravel.
Now, take a trip down through the Missouri Ozarks and you will notice their back roads are covered with little smooth, round, brown, black and gray pebbles instead of white gravel. Since the smooth pebbles are not crushed rock, they are not dusty. The smooth pebbles are scooped from the clear-water riverbeds unique to the Ozarks. You can drive all day on their back roads and never get your car dirty. Those round pebbles are a rock known as “chert,” probably the most abundant rock across Missouri.
Chert comes in many varieties and colors. Chert is composed of the mineral quartz, which is made up of silicone and oxygen, two of the most common elements on earth. Quartz sometimes forms crystals, but the quartz that makes up chert is in the form of microscopic grains. The variety of colors in chert results from numerous impurities, such as iron. These color variations give chert several different names.
Dark gray or black chert is usually called flint. Native Americans used flint for making arrowheads and other useful tools. Chert flakes off, when broken, leaving very sharp edges. They would usually strike the arrowhead with another rock to chip away, but sometimes they would simply apply pressure to the rock with a bone or deer antler until a small chip broke off. The process continued until they had a point. Indian sites such as Arrow Rock, Missouri are littered with many small pieces and flakes of chert left from this process.
Red chert is known as jasper, which is considered a gemstone. Some chert made up of bands of various color is called agate. Back in my marble-shooting days as a young lad, I was very proud of the “aggie” my grandfather gave me. Most marbles today are made of glass, but our grandparent’s marbles were made of agate. Some aggie shooters have bands of red, pink, purple, gray and green.
According to my friend Cheryl Seegar of the Missouri Geological Survey, a special variety of pink chert called Mozarkite is especially colorful and distinctive in appearance. Named for the Missouri Ozarks, the beauty of polished Mozarkite is prized around the world for jewelry making and has been named the state rock of Missouri.
Reference: “Missouri’s State Symbols,” by John C. Fisher.
To reach Ted W. Stillwell send an e-mail to <email@example.com or call him at 816-896-3592.