Sandstone formation

Looks like sandstone to me.

The majority sandstone is composed of quartz & feldspar because these are the most common minerals in the Earth's crust.

we would call this kind of sandstone an "ARKOSE". Whenever it appears that the feldspar is at or more than about 25%.
If its mostly just iron stained quartz grains , we call it an arenite.

You could have either, its hard to tell even when magnified.
Tosee how it was fomed, we really need to look at it ON edge to see the layering because they give information on how it was deposited.

Thanks for the quick answer, but the question on your answer is how this stone activate metal detector with selection "precious metals"( i know that mostly is iron). Is it possible to have another kind of metals?

Thanks

you didnt say that the rock sets off a metal detector. What kind of metal detector? EM/Gaussian/ Magnetometric?

Fe can set off two of them and if youve got a heavy enough concentration of other associates (Ni Ti Ag etc) itll set off a gaussian too (those are the little metal detectors that you use to find coins an stuff at the beach--They have discriminating circuits that are kind of variable in sensitivities (based on the price of the detector and its electronics))

Hi, I used Garret ACE 250 for different purpose but it pick up these stones instead. I have sent the stone to laboratory and will find out what it is. What pick up my curiosity is that I found this kind of stones in the ancient roman place and all of them had this hard formation in the middle. I told is result of some kind of heat treatment.
Thanks

did you use a "pinpointer" to see just where the hit was coming from on the rock? or was it from the soil?

I just scan the area and when start busing I dig little bit, remove the stone and check the same area-nothing. Then I scan the stone and again detector went off. Using this method I found couple of the same stones in the area. I looked the stone with magnifier glass and there was shiny(some white some looks to me yellow)particles. I broke one to small pieces and then I noticed that formation in the middle.