'Ashes' in the Bible

Daughter of my people, clothe yourself with sackcloth, and wallow in ashes! Mourn, as for an only son, most bitter lamentation; for the destroyer shall suddenly come on us.

Wail, you shepherds, and cry; and wallow [in ashes], you principal of the flock; for the days of your slaughter and of your dispersions are fully come, and you shall fall like a goodly vessel.

The whole valley of the dead bodies and of the ashes, and all the fields to the brook Kidron, to the corner of the horse gate toward the east, shall be holy to Yahweh; it shall not be plucked up, nor thrown down any more forever.