This is a superb, extra-large specimen of very finely branching, exceptionally sharp PSILOMELANE DENDRITES on LIMESTONE from Solnhofen, Germany. The natural, intricately detailed patterns on this limestone were formed in the Jurassic period, about 160 million years ago. Mineral rich water with high concentration of iron and manganese migrated into microscopic cavities between the layers of limestone, creating these stunning patterns, that have been mistaken for fossil ferns. Although they look like they were painted on the rock (and have been called picture rocks), this is a completely natural formation. We purchased this specimen from a German dealer who was set up at the Tucson Gem, Rock & Mineral Show. After looking over all of his material, we high graded the finest examples - and this was one of the prize finds of that day.
The dendritic markings on this thin slab of limestone look like a fossil of a delicately branching sea fan, but this is not a fossil. It is a natural mineralogical formation that was created when waters rich in iron and manganese (also called psilomelane) infiltrated the microscopically thin space between layers of pale tan limestone. The stunning patterns on this specimen, which are colored a chocolate brown with red highlights, make this an interesting and attractive specimen of the unusual mineralogical formation called dendrites.
Extra-large 7.7" large cabinet size
Intricately detailed dendrite formations
Great contrast with light tan limestone
7.7" x 6.1" x 0.6"
Medium 2" Peg Stand