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Geological processes and formations.

V některých částech dolu se stále ještě těží. Foto, ilustrace: Profimedia

Fossilised teeth | via Jeff Schultz on Flickr

Veszelyite. One of the minerals called phosphates. All phosphates have the phosphate group, PO4, in their chemical composition. Many phosphates form from the chemical alteration of other minerals in the presence of oxygen. Group: Phosphates. Image Number: 97-35129. Catalog Number: 148368. M. Stuart

The Dynamic Earth @ National Museum of Natural History

Smithsonite. The mineral was named after James Smithson, the British chemist and mineralogist who first recognized it as a distinct mineral, different from calamine(hemimorphite). It is mined for zinc. James Smithson (1754-1829) was the founder of the Smithsonian Institution. Group: Carbonates, Image Number: MSA 62

The Dynamic Earth @ National Museum of Natural History

Liddicoatite. Slice from a single crystal of liddicoatite. The colour-zoning reveal the crystal's history, just as the rings in a tree records its past. Crystals may start and stop growing many times. In most cases, there is no way of knowing how long each phase lasted. This particular crystal changed color as it grew. The pink portion of the liddicoatite formed when the solution feeding it was manganese rich. The green part grew when the solution became iron rich.

The Dynamic Earth @ National Museum of Natural History

Ethiopian Welo opal beads, about 100 carats. The largest beads are about 10 mm diameter. | via James Picht on Flickr

Lapis Lazuli & Pyrite | via Maryanne Fender on Flickr