The Cairngorm Mountains are made of granite. This is an intrusive igneous rock that solidifies over millions of years underground, the magma having never made it to the surface. Then over the millenia, the rock layers above wear away. What happens is that the release of the pressure that the rock was feeling when it was formed causes it to expand. The expansion causes it to split vertically and horizontally. This means that many granite rock formations look like they are made out of regular blocks. Some people used to think they were built by an ancient civilisation of giants. The name "Cyclopedean" comes from the giant Cyclops in Greek mythology. I have actually only ever heard it applied to the mountains on Arran. The prominent lumps of hard rock left exposed on the horizon are called TORS in Devon. You can see them clearly along the horizon in the picture of Beinn Mheadhoin. If you can't pronounce the Gaelic, go to http://www.munromagic.com/MountainInfo.cfm/13. If you click the loudspeaker, it will say it for you.