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Saturdays attempt to identify rocks in the Great Lakes:: Chert Vs Leland Blue

Updated: May 19, 2023

Saturday attempt to help identify certain rocks. Blue chert is a rascal when it comes to Leland Blues. I get tripped up on them all the time. But blue chert can be found just about anywhere. It is a 7 on the mohs hardness scale. Chert is a fine grained sedimentary rock. The coloring of blue chert is actually a chemical reaction with manganese that gives the stone its color. Buy mostly if you break or cut the stone it will be brown inside. Chert has a few characteristics. It has a waxy feeling to the outside of the stone when dry. It also looks very chalky out of the water. Any brown coloring is usually an indication of chert. It also contains silica mineral chalcedony. The are a couple tell tale signs to tell the difference between Blue Chert and Leland Blues. Leland Blue slag is actually glass. If there are shiny spots resembling chipped glass then you most likely have slag. Also with slag, there usually are a lot of little pock marks on the glass. Those are made from rapidly cooling the molten slag. Blue slag will also tend to be of a vibrant color or transparent in places. Chert is a solid stone. Chert will, as I said above, will be waxy. The chalky look will lead you to an identification of chert as well. There are alot of different cherts out there. I'm kinda just focusing on Blue chert and Leland Blues. Let me say that I am not a geologist. If anyone would like to add or correct me please do. I have added some photos so you can see some differences. There are so many different types of chert as well, blue chert, banded, brown, green and jasper chert to name a few. Bear with me as I am learning with you. I hope this helps a little! Questions are welcome. I will try to answer the best way I can. Make your day Awesome! Happy hunting!

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