Note the many different shapes of nannofossils visible here, and the 10 micrometer scale bar. Manganese Nodule field from the seafloor near the Drake Passage. 3 views of the same tektite. Note the ablation features, formed during passage through the atmosphere. Penny for scale.
Larger fragments are probably shell material.
Another Calcareous Nannofossil Ooze from 30 million year old sediments from the South Atlantic, at about half the magnification of the above sample. Note 10 micrometer scale bar. Mostly benthic foraminifera in a beach sand. Gun Beach, Guam. The olivine is contained within the basalt that forms the Hawaiian Islands, and is released when the basalt weathers.