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The flat surfaces on this rock, from the Castine Formation, are natural fractures called joints. This is an example of columnar jointing, a polygonal jointing pattern created by the shrinking of the basalt as it cooled.

Location: Condon Point, South Brooksville, Hancock County

Gift of The Vaaland Club

Specimen Sponsorship: $5,000

basalt mmgm rock garden specimen

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