OWYHEE 'PICTURE JASPER' - Oregon, USA

OWYHEE 'PICTURE JASPER’

Owyhee Mountains, Oregon, USA

Jasper is an impure and opaque form of silica, sometimes banded in shades of colours. This ‘Picture Jasper’ is not strictly a jasper but a fine-grained and very hard siltstone. 

The banding was formed by the rhythmic precipitation of iron oxide as water percolated through the rock over millions of years. The iron diffused through the porous rock in pulses or waves creating distinct bands that scientists call ‘Liesegang rings’, but the process is still not fully understood.

This example is an unpolished slice but it has an extremely smooth surface.  It has a cut base so that it displays well without a stand.

Presented in a lidded gift box.

​​Click on a picture for a larger image