Framboids. By David Rickard. Oxford University Press, 2021. Hardcover, pp. xxv+334. Price GBP 64.00. ISBN ISBN 978019008 0112.

Framboids are microscopic, subspherical aggregates of pyrite microcrystals, where the sulfide is mainly microbiological in origin: a framboid may contain fewer than 100 or more than 500 000 microcrystals. The sizes of the microcrystals span however a much smaller interval. Framboids are ubiquitous but require unique conditions to form. The book by David Rickard, world authority on sulfide chemistry, geochemistry, geomicro-biology, biogeochemistry and ore geology, opens the doors of this fascinating world. The importance of these minuscule aggregates cannot be underestimated, if we consider that pyrite nanoparticles contribute a significant component of the nanoparticulate budget of the oceans [ . . . ] and may contribute up to 10% of the dissolved iron emanating from black smoker hydrothermal vents (page 109)