MINERALS
Below are pictured some of the London Clay minerals that the collector can expect to find commonly on the beach at Sheppey.

Natrojarosite (Sodium Iron Sulfate Hydroxide) occurs as a dustlike mineral throughout the London clay of Sheppey. It is yellow in colour and very transient in nature. Rain will wash it away. Often forming around carbon deposits or pyrite and only seen in the dry clay of the cliffs. This specimen was collected in 1999 by George Ryback at Warden Point, but it is very common and can be found throughout the section.
 
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Natrojarosite forms naturally around pyritic woody deposits in the clay. However it is very transient in nature being easily washed out during rainy periods
     
Selenite Gypsum (Hydrated Calcium Sulfate)crystal formed in the clay from decaying pyrite, wash out of the weathered clay
A more unusual form of selenite which is formed at the top of the section at the junction with the overlying strata. This found only after a massive rotation where the beds are brought down to the beach level, and is characterised by the orange colouration.
Baryte - sulfate of barium, BaSO4 - and calcite - calcium carbonate, CaCO3 - form inside the chambers of the septarian nodules that wash onto the beach. The orange septaria often have the best formed specimens.
Pyrite - bisulfide of iron, FeS2 - forms inside the septarian nodule, and is usually associated with logs. The colouration varies and can range from a golden colour, with oxidisations running through reds, green and blue as in the example above. The brown weathered marcasite or white iron pyrites commonly found accumulating on the beach weathers first to grey and then to a rusty brown. It is less stable than the yellow pyrite even though it has the same chemical composition.