Quartz, Natural Ferruginous/ Hematoid Quartz/ Fire Quartz AAA BraceletNatural Ferruginous Quartz Natural Ferruginous Quartz, also known as Hematoid Quartz or Fire Quartz, is a variety of quartz characterized by inclusions of iron oxides such as hematite or limonite, which impart red, brown, or yellow hues to the stone. Rarity: Ferruginous Quartz is not typically classified as a rare gemstone. However, high quality specimens with distinct coloration and clarity can be considered rare and are sought after by collectors.