Help id

[Blakectx]

Found this in central Texas. It is heavy but not metallic as a magnet will not stick. Can you help to ID?

[Creek - Don]

It's a Pyrite. Here were my finds.  Mine were also rusted like that, but cleaned with hydrochoric acid.  Shines like chrome. 

[Mark Kmiecik]

Most iron compounds are not attracted by magnets. There's only a minor attraction to nickel and no attraction to gold, silver, tin, aluminum, copper, magnesium, titanium, tungsten, chromium, cobalt, zinc, manganese, lead, palladium, platinum, potassium, sodium, vanadium, gallium, indium, mercury, thallium, neodymium, or any of the many others that I can't remember offhand. So a magnet is only helpful in the identification of a few iron compounds or the elimination of those few, which leaves thousands more as possibilities. 

 

So you can't really say with any reliability that a specimen is non-metallic, or even non-ferrous, because it was tested with a magnet. The magnet test is only useful if it attracts the specimen.

 

That's what I love about fossil hunting. It can be so informative and makes you smile and have fun as you learn.

 

P.S. -- It looks like it's an ironstone concretion. Deep red and brown color is commonly indicative of the mineral's iron content. Google "ironstone concretions texas" and check out the images.