(With time and some human intervention) rock becomes sand; sand becomes glass. This series of work combines the first and last stages of the process and what you are looking at is two versions of the same material. It also, in my head, references transitions generally, that some (e.g. ice to water to steam) are reversible, that others (e.g. ageing: rock to sand to glass) are not.
That’s the essence of what the work is about for me.