Sylvia Rose14 hours ago4 minAluminum(III) Oxide: Secrets of Precious GemstonesAluminum oxide or alumina (Al2O3) is the secret to the composition and allure of precious gems such as sapphire and ruby. This white,...
Sylvia Rose15 hours ago4 minCorundum: Secrets of Valuable GemstonesCorundum is a mineral composed of aluminum oxide. Living deep within the Earth in an environment of intense heat and pressure, the...
Sylvia RoseSep 13 minGoethite: The Other Iron-Rich MineralGoethite is common but like hematite a remarkable iron oxide mineral. In geology and mineralogy, goethite has piqued the interest of...
Sylvia RoseMar 35 minLimonite: Ancient Earth PigmentsLimonite is an iron earth mineraloid among the first colors of the Stone Age palette. Grinding limonite produces yellow ochre. Other...