焦磷酸钙菱形结晶在红感光板偏振光下呈蓝白色（弱正双折射）。焦磷酸钙结晶沉积病（有时称为“假性痛风”）在50岁以上人群中并不少见，它能引起膝关节、腕关节、肘关节、肩关节与踝关节的急性、亚急性或慢性关节炎。这种关节病变是进行性的，但大多数人的这种病不严重。
This rhomboid shaped crystal of calcium pyrophosphate, which appears bluish-white (weak positive birefringence) by polarized light with red plate. Calcium pyrophosphage crystal deposition disease (sometimes called "pseudogout") is not uncommon in persons over the age of 50, and can lead to acute, subacute, or chronic arthritis of knees, wrists, elbows, shoulders, and ankles. The articular damage is progressive, though in most persons the disease is not severe.