Orpiment — a crown of “King’s Yellow” thorns

Orpiment consists of layered sheets of arsenic trisulfide held together by weak van der Waals forces affording perfect cleavage parallel to the sheets. It is also a semiconductor with a bandgap suitable for absorbing visible light. It forms in hot springs with arsenic-rich water. Orpiment was used as a yellow pigment in ancient paintings, manuscripts, and dyes in Egypt and Europe. It was used as a medicine in China, even though it is extremely toxic. It was used to tip arrows with poison. It also has been found in the wall decorations of Tutankhamun’s tomb and on the walls of the Taj Mahal.

Orpiment on Calcite
From Jiepaiyu Mine, Shimen deposit, Shimen Co., Changde, Hunan, China
23 x 17 x 9 cm (9.06 x 6.69 x 3.54 in), Surround video