Re: petrified wood, pyrites


Yes, calcareous fossil wood would raise the hardness, but of course this
depends on the surface area of the wood. A single block of wood would
affect hardness much more slowly than the same mass ground up into small

Similarly, the surface area available for colonization by bacteria is much
less than a properly milled silica substrate of equal mass.

Pyrites (fool's gold) is essentially iron sulphide crystals. Pyrites decays
very quickly in contact with oxygen to form sulphuric acid and iron oxide.
I would suggest neither is welcome in an aquarium.

Many fossils here are pyrites, and even in good conditions (dry cupboards)
have a shelf life of only a few dozen years.

All the best,



From  Neale Monks' Macintosh PowerBook, at...

Department of Palaeontology, Natural History Museum, London, SW7 5BD
Internet: N.Monks at nhm_ac.uk, Telephone: 0171-938-9007