Iron in Stone

Have some stones… they have a lot of yellow color in them . . .
some more than others . . . . a very ‘gold’ tone to them. I believe
the yellow and the gold tone is due to the iron in the stone . . .
Believe the ‘gold’ tone is due to the oxidation of the iron… If the
is true(???), then how do I bring out the the gold tone in all o the
stones … that is, how do I get the iron in the all stones to
Oxidize . . . I view this is as like a natural patina. . . . Any
thoughts as to acid (Muric, Nitric, etc.)?? Thanks, Jim Chambers

Well, first step would be to be sure of what you have in the first
place! If it’s a metallic stone, a golden color might indicate iron
pyrite, and the color is not an oxidation product, but the natural
color of the material in that form. Marcasite would be more of a
silvery color, and I don’t think you can change one to the other.
Limonite is a hydrated iron oxide, and it is more earthy than
metallic, and is yellow. Can’t do much with it at all. A sturdier form
would be ironstone, as in boulder opal matrix… but that’s reddish
brown rather than yellow or golden.

Jaspers can come in gold and yellow tones, so can agates. Agate can
have rutile inclusions… So… the answer is… it all depends! :>
Seriously, can you describe the material a little more? Is this rough
material, cut, crystalline, metallic, or something else??


| Carol J. Bova @Carol_J_Bova |
| The Eclectic Lapidary e-zine |
| |

Perhaps what you’ve got is some of the Limonite Topaz which I saw a
good bit of about 5 years ago. It is a clear Topaz with needles of
yellow limonite inclusions aligned inside. I don’t know of any way to
treat it to get more yellow out of an individual stone. I did see a
couple of stones that had been irradiated and turned blue.

jim - except under very specific circumstances we won’t see for a
while what you see in the rock rough or stone is what you get. the
colors were determined from the mineral inclusions in the matrix
(mother rock, host material, etc.) centuries before any eyes ever saw
it. i.e., you can’t get malachite or turquoise by chemically altering
the copper in a piece of rock rough after it’s been dug up.
alchemists used to make a living convincing kings & other fools this
could be done to get gold - however, if you do trade some magic beans
that work on this principle please let me know - i have about a half
of a ton of rough i’d like to transform into something else. ive