Almost part of the Scottish Parliament building

Today my wife went to visit the Kemnay Quarry as part of a school delegation. This is the place where the granite material used to build the infamous Scottish Parliament Building. She was given, as a souvenir of her visit, an off cut from the actual rock that was trimmed to form the blocks that are now incorporated in the building in Edinburgh. I have been in the parliament buiding only once and I have to confess that I was surprised to see that the internal walls are made of plain grey concrete. It is finely polished – but not my impression of a suitable decorative material for such a building. Here is the rock sampl