Romboedr

Romboedr (romb va Yunoncha hedra — asos, yon, tomon) — hamma yokdari teng romblar bo’lgan parallelepiped. Ba’zi kristallarning, masalan, Island shpatining kristallari Romboedr shaklida bo’ladi. Parallelepiped faqat uchinchi tartibli simmetriya o’qiga ega bo’lgandagina Romboedr bo’ladi.