For Aachen Cathedral some pinnacles had to be replaced. The old ones were worn and had cracked because of rusting iron and because the layering of the stone was not properly applied. The deposition direction of the stone should preferably be processed horizontal, otherwise there is a risk that a long vertical slice breaks off. In this case, they applied it vertically.
The material for these pinnacles is Irish bluestone. It is virtually the same material as the more famous Belgian bluestone, but it is a bit more evenly toned (some would say more boring) and easier to work in: it is slightly less hard and there's less tool wear because it contains less silica.
I got supplied with the old model and new blocks of Irish bluestone (Kilkenny limestone). The four crockets of the finial are not connected to each other in the middle. With an angle grinder, I can not cut all the way down to the shaft, but with a chainsaw it's no problem. This speeds up the carving significantly! Of course, a large stonesaw machine could also fix this, but I don't own one. For firmness I could even leave part of it still attached, so that the stone wouldn't break too easily.
Shaping the forms
Finials are essentially the same as crockets. A gothic pinnacle contains from bottom to top a few rows of leaf shaped ornaments (the crockets), which are usually crowned with more intricate leaf shapes which are opposed to each other in a cross shape (the finial).
These crockets and finials of Aachen Cathedral are likely postwar copies. They were certainly not carved all that exciting at the time. I have, without deviating much, applied slightly more tension in their shape. The overall shapes of the finial are all located within the same plane. That makes it easy to quickly precut these flowers in the beginning.
The simple water leaf crockets I carved a bit deeper, and made the outlines a bit more graceful and sharper (see below). In 1993 I first learned to carve crockets and finials, and in the past 25 years I've made a lot of these, but not often in bluestone before. Because Irish bluestone or Kilkenny limestone, is, as its Dutch name denotes, a relatively hard stone, it is natural that the shapes are kept so simple. But even the simplest of water leaf crockets has its own charm, and it is essential that its shape keeps the tension and that after generations of copies to copy we're not just left with a vague sort of shape. That still makes it somewhat interesting for me to carve: the search for a beautiful shape and its tension.
It is intended to replace many more pinnacles from Aachen Cathedral in the future.