A form of silicate: ie,_ is (4)
I have -a-c so the answer seems to be talc. But, yet again, I don't understand the wordplay. And, yet again, it's the last one. So infuriating! But it is certainly helping me develop as a cruciverbalist (I've just learnt that word. The computer doesn't believe me and has tried to change it!) when you kind people explain.
Steven
Sorry but may I have a further bite at this one please? What is the reason for the comma and the underscore? Is the latter supposed to be a minus sign?
Steven