- probably named after the Persian word for dragon blood because of its characteristic red colour
- used since ancient times as a pigment
- Formula: HgS
- Space group: P3121 (No. 152) or P3221 (No. 154)
- Crystal system: trigonal
- Crystal class: 32
- Lattice parameters: a = b = 4.1347(6) Å, c = 9.4451(3) Å, α = β = 90°, γ = 120°
Crystal structure (click on the pictures to download the VESTA file):
View along the c axis.
View along the a axis.
- the crystals structure is characteristic of chains with alternating sulfur and mercury atoms, which form helices with the helix axis running parallel to the c axis.
- These helices are also the reason why crystals of cinnarbar are optically active (see: A.M. Glazer, K. Stadnicka, “On the origin of optical activity in crystal structures”. J. Appl. Cryst. 19 (2), 1986, 108–122. doi:10.1107/S0021889886089823