The gravel pit of Sankt Jakobsberg near Ockenheim represents the most northwest place of discovery of the so-called tertiary Dinotheria sand. Here small (to 40mm large) waterworn black-and-white coloured agates occur. The black coloration of these small agates is due from micro-crystalline sulfur sulfide (markasite /pyrite).
If one is cutting such stones, develops a sulfurous, smell, which is significant for these minerals. This alone is however not the point, why one should not cut this tiny agates. They are in their natural and singular state, with their bleached and reliefied in black and white strongly contrasting surface not to improv by cutting. In their inside they show rarely interesting colors and patterns. Comparisons of the structureare showing that these agates originate from the Saar-Nahe area.
|