Unglazed Porcelain Streak Plate, 12-Pack

This pack of 12 streak plates is made from off-black unglazed porcelain. Streak testing involves drawing a mineral across the plate to observe the color of the powder streak left behind, which is often more diagnostic than the color of the mineral itself. The unglazed porcelain surface has a hardness of approximately 7 on the Mohs scale, allowing it to test minerals with hardness below that level. The 12-pack provides enough plates for classroom use and group testing exercises.