| Zirkelite | |
| Category: | Oxide mineral |
| Imasymbol: | Zke[1] |
| Strunz: | 4.DL.05 |
| System: | Isometric |
| Class: | Hexoctahedral (mm) H-M symbol: (4/m 2/m) |
| Unit Cell: | a = 5.02 Å, Z = 4 |
| Color: | Black, reddish brown |
| Habit: | Crystalline, metamict, pseudocubic |
| Cleavage: | None |
| Fracture: | Brittle |
| Luster: | Resinous |
| Streak: | Brownish grey |
| Diaphaneity: | Subtranslucent to opaque[2] |
| Density: | 4.7 |
| Other: | Radioactive |
Zirkelite is an oxide mineral with the chemical formula . It occurs as well-formed fine sized isometric crystals. It is a black, brown or yellow mineral with a hardness of 5.5 and a specific gravity of 4.7.
Zirkelite was first discovered in Brazil in 1895. It was named for German petrographer Ferdinand Zirkel (1838–1912).
Initial discovery was from the Jacupiranga carbonatite, Sao Paulo, Brazil. It is also found in Canada, Kazakhstan, Norway, Russia, South Africa, the United Kingdom, and the United States.