Dimensional stability of the shell mould is a key factor to meet the requirements of dimensional accuracy of the castings. Additionally to thermal expansion of the ceramic raw materials, changes in the mould dimensions may occur due to distortions during the pre-firing of the moulds or because of deformation under the weight load of metal at high temperatures. Fused minerals provide not only the necessary refractoriness and resistance against attack by the molten alloy but can also be used to build shells with exceptional hot dimensional stability, for instance to withstand high temperatures for a long time in SX and DS castings or to allow tightest dimensional control for the production of turbo charger wheels. This paper discusses thermal expansion, hot dimensional stability, and shell removal properties of shell systems based on Fused Minerals.