Today a lot of machines are made from quartz(sand) and resin. The ratio of binder and different sieves of quartz is important to get strength and stability. The amount of resin is small as it is a binder "glueing" the quartz grains together. The different sieves are necessary to essentially fill the volume with quartz. Done right, the quartz will be the material that determines the expansion/contraction. For each metre of casting, only a tiny fraction will be the binder between the grains. So any expansion/contraction of resin will have very little influence. The end result will be more or less a stone cast cold in a shape of your desire.
This has been discussed on a German forum Peter's CNC-ecke for those of you that can read the language, here is one thread:
http://5128.rapidforum.com/topic=115181924767
It's a quite interesting subject, as the result is thermally and in other ways stable. Also it is good at absorbing vibrations.
Examples:
http://www.epucret.de/maschinenbau_anwendungen.html