I have set a lovely piece of agate, one that has been called
"dragon vein" or "dragon skin" or even "fire agate." It has, or I
should say HAD, a lovely white fissuring in the blue material where
it looked cracked.
I can’t tell you exactly what happened to cause your stone to change
but I can say that the only thing “natural” about this material is
that it is chalcedony. The “crackled” effect is probably due to some
sort of heating and quenching process followed by bleaching, and most
of its various colors are the the result of dyeing.
The current (Winter) issue of Gems & Gemology from GIA presents a
brief study of this stuff, which is all over Tucson and the auction
sites under the names “Crab Fire Agate,” “Fire Dragon Veins Agate,”
“Crackle Fire Agate,” etc., even “Natural Fire Agate.”
As the G & G researchers say: “…we recently learned this material
is being represented as fire agate – a brown chalcedony that
displays multicolored iridescence and commands a higher price than
other chalcedonies. The beads we examined bear no resemblance to fire
agate, and it is misleading to refer to them as such.”
As a cutter and seller of genuine natural fire agate I have been
concerned and angered by the misrepresentation of this highly treated
and low value material.