clinker vs scoria

clinker

noun
  • Hardened volcanic lava. 

  • Someone or something that clinks. 

  • A scum of oxide of iron formed in forging. 

  • Slag or ash produced by intense heat in a furnace, kiln or boiler that forms a hard residue upon cooling. 

  • A very hard brick used for paving customarily made in the Netherlands. 

  • An intermediate product in the manufacture of Portland cement, obtained by sintering limestone and alumino-silicate materials such as clay into nodules in a cement kiln. 

  • A style of boatbuilding using overlapping planks. 

  • fetters. 

  • A mass of bricks fused together by intense heat. 

verb
  • To convert or be converted into clinker. 

scoria

noun
  • Rough masses of rock formed by solidified lava, and which can be found around a volcano's crater. 

  • The slag or dross that remains after the smelting of metal from an ore. 

How often have the words clinker and scoria occurred in a corpus of books? (source: Google Ngram Viewer )