catachresis: strained or paradoxical use of words either in error (as `blatant' to mean `flagrant') or deliberately (as in a mixed metaphor: `blind mouths')
rhetorical device: a use of language that creates a literary effect (but often without regard for literal significance)
feldspar: any of a group of hard crystalline minerals that consist of aluminum silicates of potassium or sodium or calcium or barium