[3] It has a tetragonal crystal structure at room temperature, which then transforms to an orthorhombic (Pearson symbol oP28, Space group Pbam, No.

The best known natural specimens come from Broken Hill, New South Wales, Australia, where they formed as the result of a mine fire.

Although red lead still offers more accurate markings since it doesn't flow as readily as engineer's blue under pressure.

High concentrations can be absorbed through skin as well, and it is important to follow safety precautions when working with lead-based paint.

Chronic poisoning displays as agitation, irritability, vision disorders, hypertension, and a grayish facial hue.

In the ancient and medieval periods it was used as a pigment in the production of illuminated manuscripts, and gave its name to the minium or miniature, a style of picture painted with the colour.

In 1504 the portcullis at Stirling Castle in Scotland was painted with red lead, as were cannons including Mons Meg.

In traditional Chinese medicine, red lead is used to treat ringworms and ulcerations, though the practice is limited due to its toxicity.