i didnt know where to pose this question, so i made a new thread...
the dolmans and entrances to the tombs are made with stone obviously..my question is what KIND of stone...is this a granite?
seems to me that limestone wouldnt last thruout the millennia they way these monuments have...
im guessing granite or someone even suggested dolomite?

Most that I've seen are made with local stone. One of the most famous Irish dolmens (certainly the most photographed!) is Poulnabrone on the Burren in Co. Clare and it's made with limestone.

A couple of exceptions are Newgrange and Stonehenge. The smaller stones used to make the bulk of Newgrange are from the Boyne valley in which it stands but the large decorated stones are Wicklow granite. The white stones around the entrance are from the Mourne mountains. (It may be the other way around!) Stonehenge is made with stones that were quarried in south Wales.

i knew you'd know ...lol

the Mourne Mountains are limestone then?

No, they're mostly granite but they contain substantial amounts of white quartzite.

Just had to correct an error with reference to the construction materials used at Stonehenge. Only the "Bluestones", the horse-shoe-shaped structure, were brought from the Prescelli Mountains in South Wales. The larger (up to 60 tonnes) stones that form the trilithons, the lintelled circle and the Heel and Slaughter stones were quarried (or just dug up and worked) within a few kilometres of the 'Henge site on the Marlborough Downs and are made of Sarsen Sandstone. Both operations, although carried out maybe centuries apart, were engineering feats on an unimaginable scale.

normally they just used whatever was available, be it limestone or granite or sandstone. sedimentary rocks that can be cleaved into slabs seem to be slightly favoured for the cap stones but only if locally available