Less spectacular than peacock ore but slightly more interesting is a metallic stone called hematite. Chances are that you have seen this black, shiny stone on jewelry. In that setting, it resembles something between a rock and a metal (as it should - the formula for hematite is Fe2O3, iron and oxygen).
Wait, iron and oxygen? Doesn't that usually lead to rust?
Ohhh yes. The name "hematite" comes from the Greek word for "blood."All hematite has at least one rust-red streak in it, thus the colorful association. The element iron makes both hematite and human blood red; what a fitting name, science!
Don't let the shiny metallic appearance fool you; hematite has been used for rich red coloration throughout much of human history. Hematite-rich clay, called ochre, has been used to turn things red since the idea of "dye" first entered human consciousness. The earliest use of a hematite compound as a pigment goes back to the Middle Stone Age. Hematite's the real bloodstone - fuck that other bloodstone that's supposedly the birthstone for March.
"Christmas tree stone" should be just as valid.
The crazy thing: Hematite is a waste product. It is very easy to get hematite via simple chemistry (such as steelwork). It is a common by-product in iron mines as well. Nobody deliberately makes hematite; nobody really has to.