The term 'KIND OF SPRING' can be solved by the crossword solutions COIL (4 letters), SPA (3 letters), and MINERAL (7 letters). A COIL spring is a type of mechanical spring that is made from a metal wire that is coiled into a helix shape. A SPA is a recreational facility that offers MINERAL-rich water treatments, such as hot tubs, saunas, and massages. MINERAL springs are natural sources of water that contain minerals, such as sulfur, calcium, and magnesium.