unfortunately this is common with much of the material on the market-
it has fractures all over the cut surface but dealers often 'polish’
it before a show if they aren’t selling it for under two bucks for
the average 2 inch specimen. Where the mineralisation has occured you
can polish it again and then seal it with marine varnish (waterproof
and remains clear) if the fractures are hairline or less (almost
invisible) soaking in a preparation like Opticon is ok-again if the
fractures are small. If portions of the mineral have actually
crumbled from exposure to light and acrid or salt air then it’s a
matter for a resin fill as the material will continue to
disintegrate and the only preparation useful is one that will both
fill in large gaps and seal the surface- you can mix powdered /
crystalline pyrite / marcasite / limonite into a small amount of
resin to fill in obvious areas then after it is fully cured polish it
to appear congruous with the rest of the pieces, then seal it with
the necessary number of layers of resin to level the surface’s
appearance. Strictly adhering to manuf. curing instructions between
applications to prevent cloudiness in time (gasses will try to
escape from the specimen as long as any surface remains
unsealed).Make certain the resin isn’t one that remains flexible -you
want it to be hard. After opticon and the hardener it will polish
better than any epoxy…
