The building is built of rose granite quarried in Ortonville, with many stones greater than 20 tonnes in weight. The granite was originally only going to be used for the foundation of the building, with brick used for the upper portion. However, the public appreciated the appearance of the foundation so much that they lobbied for the entire building to be made of granite. This may be a reason for the significant cost overruns — it was originally expected to cost only $1.15 million.