Jasperoid
![Hematitic silica alteration 'jasperoid', Yarlarweelor mine, Glengarry Basin, W.A.](/Images/godic/202501/21/Jasperoid3449.jpg")
Jasperoid is a rare, peculiar type of metasomatic alteration and occurs in two main forms; sulfidic jasperoids and hematitic jasperoids. True jasperoids are different from jaspillite, which is a form of metamorphosed chemical sedimentary rock, and from jasper which is a chemical sediment.