Stone types for carving
The Museum Building
On the Museum Building the decorations are carved in Portland Stone. Why was Portland Stone utilised for the carvings and were other alternative stone types available for this purpose at the time?
Since the golden age of public and church building in Dublin from the 1750s to the 1840s the stone of choice for the exterior façades of buildings was grey Leinster Granite for ashlar walls and creamy Portland Stone for decorative features. This preference is well exhibited in Dublin buildings such as the General Post Office, the Parliament House on College Green, the West Front and Parliament Square of Trinity College, and St Stephen’s Church, Mount Street.
Portland Stone in the 1850s was not the only lithology (rock type) available to architects and stone carvers, and while it may have had historical precedence in using it, the stone also was more suitable for the highly elaborate carvings that were to be undertaken to decorate the building, and which would be viewed at relatively close quarters, particularly in the hallway of the Museum Building. Some of the English sandstones and limestones from localities such as Purbeck and Ancaster were less resistant and could not be cared in such details as Portland.
This stone from the Isle of Portland is oolitic (composed of tiny calcareous spheres), that are firmly and closely cemented together which made the stone compact and durable. It was moderately easily worked in all directions, took a very sharp line and could be carved in splendid complexity using a variety of fine chisels and drills.
It is therefore unsurprising that Deane and Woodward selected the stone favoured over the last century and a half for the exterior of the Museum Building. However, this was one of the last buildings in Dublin to use such materials: only a decade later did the Victorian preference for polychromatic exteriors become fashionable. In the vicinity of Trinity in banking and other commercial buildings this adoption is very much in evidence with English and Scottish yellow, red and purple sandstones contrasting with Irish grey granite and limestone, and carvings were executed in Irish grey limestone, red and yellow sandstones as well as Portland.