Pyrite is a weird mineral . . .
This page from wiki shows something similar!
Xenoid - 2-4-2011 at 12:54
Pyrite is unstable in the presence of air (oxygen) and moisture. It breaks down to form a whole range of hydrated iron sulphate minerals as well as
sulphuric acid. The sulphuric acid will react further with silicate minerals in the gangue to form other sulphates and also release SiO2. The gel like
material you observe is probably a mixture of hydrated sulphate minerals and silica gel.
Pyrite is hard to preserve, and should be kept in a moisture free environment. I have seen pyrite "specimens" in collections which were just a pile of
powder!
Edit: This paper gives some idea of the complex alteration products!
Alt.— Marcasite being relatively unstable is easily altered.
Specimens disintegrate [easily!] with the formation of ferrous sulphate and sulphuric acid.
I keep mine (mostly Marcasite on wood) in a jar with CaCl2.
See Dana or some such for a simple chemical test to tell them apart. cyanureeves - 2-4-2011 at 17:04
Pyrite is wierd. Not having ever seen platinum ore I thought I had struck it rich with some pretty silver looking pyrite I had secretly stashed
away.My weak nitric acid wouldn't dissolve it so it made me think more so that I had platinum on my hands. Aqua regia had to be used and it make a
bright orange red solution as it dissolved,this gave me enough confidence to do the heated spoon test. I put some grains on a spoon and passed it over
a flame and it shot out like a bullet. I added some carbonate to the solution and am going to add acetone to make some sort of sweet smellin oil of
iron out of the rust I now have.chemrox - 2-4-2011 at 19:59
The photo looks more like galena than pyrite and the gangue material may be hydrous lead II hydroxideblogfast25 - 3-4-2011 at 06:59
And I've seen samples of pyrite crystals preserved in atmospheric conditions, without any degradation for decades...The WiZard is In - 3-4-2011 at 12:44
The photo looks more like galena than pyrite and the gangue material may be hydrous lead II hydroxide
A simple streak test will tell. La mineral is rubbed on a piece
of unglazed white porcelain. The sell 2" squares for this, however,
to prove you experimental bona fides you could break your favorite
coffee cup or a piece of your wife favorite porcelain ware — and use a broken edge.
Galena streaks lead gray.
Pyrite greenish-black.
Probable there dobe a borax bead test to distinguish them.
It is never toooo early to start you Christmas shopping
a pyrite sphere perhaps?!
