They probably faced this difficulty by growing on, or within, mineral surfaces such as sulphides and/or clays.
Targets were baited with 300 g of lamb liver and 10 g of crushed sodium sulphide.
It is significant that fissures 1, 2, 9 and 10 have metal sulphide veins associated with the fossil-bearing and usually black sediments.
It is possible that these marcasites could have been precipitated from the same sulphur-bearing fluid as the main phase sulphides.
Evolved hydrogen sulphide was carried in a nitrogen stream to a silver nitrate trap and precipitated as silver sulphides.
Evolved hydrogen sulphide gas was carried in a nitrogen stream to a silver nitrate trap and precipitated as silver sulphide.
There was no such difference in the presence of sodium sulphide.
Sulphides are rare and there is no clear correlation between the platinum-group minerals and the sulphides.
