Urea, a new mineral identical with the artificial compound, occurs as crystals associated with phosphammite, ammonian aphthitalite, and weddellite in guano from Toppin Hill, 123° 56′ E., 28° 42′ S., Western Australia. The urea occurs as elongated tetragonal pyramids, space group P4¯21m, a 5·646, c 4·701 Å, X-ray powder data are given. Optical properties: ω 1·484, ε 1·603. Chemical analysis gave urea, CO(NH₂)₂ 96·0, H₂O⁻ 0·46, Na 0.13, K 0·35, Ca 0·07, Mg 0·03, S 0·11, P 0·24, NH₃ < 1·0 %, remainder probably mainly H₂O⁺; urea 96 %, impurities 4 %. Type material is preserved in the collection of the Government Chemical Laboratories, Perth, Western Australia.