A Mani Jewel (Chinese: 摩尼珠; pinyin: móní zhū; Japanese: mani ju) or "maṇi-ratna" refers to any of various jewels or crystal mentioned in Buddhist literature as either metaphors for several concepts in Buddhist philosophy or as mythical relics. The word mani is simply Tamil, Sanskrit and Pali for "jewel", so the phrase "Mani Jewel" is in one sense redundant. However, the Mani Jewel metaphors were significantly expanded in Chinese language texts in which it was also called by essentially the same redundant name móní zhū, where the first two characters (摩尼; móní) are the transcription of mani and the third character (珠) is its Chinese translation, "jewel". The English phrase "Mani Jewel" is thus in essence a translation of the Chinese term. The use of the Mani Jewel in Buddhist literature includes various magical relics such as the wish-fulfilling cintamani as well as metaphorical devices to illustrate several ideas such as Buddha-nature (Om mani padme hum) and Śūnyatā.