Polycrystalline

A crystalline sample of a single mineral, containing many crystals. Quartzite, for example, is polycrystalline quartz.

Have a look at the quartzites (L520, L521) in the 1A Reference Series.

“Polycrystalline,” 1A Collections, accessed April 9, 2024, https://wserv3.esc.cam.ac.uk/p1acollections/items/show/242.