It is used to cover serious skin discolorations such as birthmarks, scars and vitiligo. When used together with benzoyl peroxide products, temporary yellow or orange skin discolorations can occur. It is initially white but develops yellowish-brownish discolorations with age. Streaking and ring spots are still other distinct types of discolorations. Early mines appear as light green or whitish discolorations on the leaves. Extrinsic discolorations are common and have many different causes. These discolorations are reversible but may take months to years to disappear. Pink and red discolorations are also associated in patients with lepromatous leprosy. These discolorations have led to the term "sun fungus". Over time, the painting had developed some discolorations and acquired dirt and insect excrement. Some extrinsic discolorations that are allowed to remain for a long time may become intrinsic. This would be observed as brown-black discolorations in a freshly broken root. With new technology, Yunzi stones can now be made pure white without any discolorations. Written records documenting cloudy discolorations in the lake exist from late 19th century. Identification of the coins was based upon unusual patterns of discolorations present upon the coins.