Sinter

noun form:
*the buried alive remains of ancient microbial communities;
*a chemical sediment or crust composed of silica deposited by a mineral spring;
*a calcium carbonate deposit that forms in freshwater.

verb form: to form a coherent mass by using pressure and heating without melting

Etymology: the word comes from German and is related to the word “cinder”

Sinter produced in volcanic environments provides information about the distant past when intense volcanism was widespread on the young earth. Study of sinter offers clues about possible life on other worlds.