Okay, let's start by asking some questions.
First, the brown stone. The smooth surfaces, do they feel waxy. If you have agate or chert or chalcedony in your collection, I want to know if the brown rock feels the same way.
Second, if you take a pocketknife, or a nail, does it scratch the rock? Iron is about 5.5 on the mohs scale, most silicates are around 7.0. The iron will not mark it
Lastly, if you put a strong light source behind it, does the rock allow some of the light to pass through it? Is it translucent?
There are more things you can do to assist in this identification. If you have a magnet, is either stone magnetic?
If iron scratches either and the rock is brittle that will also tell us more
Looking forward to your answers.