EXTRA, the marketplace for scientific touring exhibitions.
A) Introductory part
1) Causes of the development of pattern in mineral aggregates in general (illustrated by specimens showing patterns of different origin)
2) Causes of shape and colour of patterns in microcrystalline silica varieties
B) Display of 'figured stones' arranged according to a practical 'gemmological' system
1) Jasper;
2) Jasp-agate;
3) Agate;
4) Chalcedony;
5) (Coarse crystalline) quartz;
6) Non-silica minerals. With a glossary of agate, jasper etc. names.
C) Special exhibits
1) “Transparent beauty”: Transparent slices of agate, obsidian and cleavage flakes of mica (needs special showcase);
2) “Spherical patterns”: Polished spheres of minerals and rocks;
3) “Photos and models” (pictures and captions from the book “Achate – Bilder im Stein” by Josef Arnoth together with the original specimens);
4) A Chinese scholar’s rock (see THE section “Highlight”)