The non-red stones in this wall we are building up in Fife, Scotland are a type of whinstone.
Whinstone is a term used to describe a number of very hard stones. They are usually igneous rocks, basalt or a kind of angular dolerite.Apparently the name 'whin' derives from the sound it makes when struck with a hammer. I think it has more to do with how lucky you are in making them fit in a dry stone wall. Their natural angular contours make fitting them all together structurally AND beautifully difficult and to make it harder, the stones are very hard and often shatter off in even stranger angles if you do try to shape them. Simply put they are a challenging material to build with.
Here is an interesting example of a type of layered whinstone one comes across occasionally and that we have been working with (in combination with some local sandstone) found near the property.
Inside the softer shell of this local fieldstone whinstone there is often a hard roundish cannon ball shape .
Here are some bigger cannonballs we have had to use.
Local well built boulder-coped walls are almost entirely built of big chunks of whinstone and these walls are everywhere you look and they look beautiful (in their own rather course/uncoursed way) and more importantly they do the job.