Some embodiments include methods of patterning platinum-containing material. An opening may be formed to extend into an oxide. Platinum-containing material may be formed over and directly against an upper surface of the oxide, and within the opening. The platinum-containing material within the opening may be a plug having a lateral periphery. The lateral periphery of the plug may be directly against the oxide. The platinum-containing material may be subjected to polishing to remove the platinum-containing material from over the upper surface of the oxide. The polishing may delaminate the platinum-containing material from the oxide, and may remove the platinum-containing material from over the oxide with an effective selectivity for the platinum-containing material relative to the oxide of at least about 5:1. Some embodiments include methods of forming memory cells. Some embodiments include integrated circuitry having platinum-containing material within an opening in an oxide and directly against the oxide.