home/mineralworldagates/ Europe/Germany/Nahe-Region/Idar-Oberstein/ Gerach: sceptered quartz-crystals
Already for a long time mineral collectors are waiting for the first find of sceptered quartz-crystals in the Juchem quarry. Quartz formations in several generations were found in the geodes, however these had so far not grown together oriented after the c-axis. For the formation of sceptered quartz-crystals it requires a change of the formation conditions (supersaturation of the hydrothermal solution), due to which it comes to the preferential settlement of quartz substance at points with sufficient free surface energy (usually points and edges).
In a house-building area of Gerach, directly opposite the Juchem quarry, I could constitute a zone in the amigdaloite, in which it came to the formation of lamella quartz-crystals and sceptered quartz-crystals in the year 2001. Rykart (1989) describes a similar formation of quartz-crystals from the Canary Islands. In the strongly leached out amygdaloite I could gather a multiplicity of quartz nodules. If these were inside hollow, then therein quartz of the dirhombohedrical habit that is typical for the region ("dipyramidaler habit", "Cumberland habit") occurred.
The sceptered quartz-crystals and and lamella-quartz-crystals were formed on the surface of the nodules and are representing therefore with leaching processes connected recrystallisations. The laminated structure of this quartz refers to an intermitted rhythmic quartz formation. The size of individual crystals reached up to 30mm. Since the crystals are superficially slightly etched and their interesting structures photographically are hardly to be conveyed, I decided for its representation by sketches.
More information about this structural interesting quartz-type is given by Rudolf Rykart ("Quarzmonographie" 1989, Ott publishing house, Thun) page 244