Hydrargyrum is the Latin form of a Greek word meaning “liquid silver” - mercury. The Hydrargyrum typefaces are designed with characteristics both of a metal and a liquid. The basic shapes of the letters are generally rigid and rectangular (particularly in style C), but the forms are enhanced by fluid curves and gently rounded corners. Hydrargyrum is not recommended for use at small sizes or in lengthy passages of text. It performs best in display-sized settings.

Hydrargyrum consists of three styles, each in medium and semibold weights with matching obliques. The A style features solid, standard letterforms including the two-story a and g. Style B substitutes the a, g, M, and N (and related glyphs including numero and trademark symbols) for alternate shapes. The third subfamily takes the rectangular theme to an extreme, eliminating as many slanted strokes as possible from the letterforms. This makes some C-style letters ambiguous with one another, such as the U’s and V’s. As such, the C style is best used carefully even at larger sizes.

The Hydrargyrum fonts are style linked within each style subfamily with, for example, Hydrargyrum A Medium as the regular style, Hydrargyrum A Medium Oblique as the italic, Hydrargyrum A SemiBold as the bold option, etc.