Amorphous Urates. Amorphous urates are crystals that form in acidic urine. These crystals are composed of the elements sodium, potassium, magnesium and calcium. They appear yellow or yellow-brown.he appearance and acidity of the urine sample in question can point to specific types of amorphous crystals. However, occasionally amorphous crystals are misidentified as bacteria. Crystals are found in healthy patients' urine, but they may indicate liver impairment or live disease.