Old gold color, similar to olive color. I don't know why they call it that. This is probably the color of gold before processing. But I'm not sure.
Old gold is a dark yellowish brown to medium brown color, like oxidized gold. It is the traditional color of college and professional sports teams representing the University of Notre Dame, whose official colors are "old gold" and navy blue.
The old gold of the Fighting Irish was formulated in 1913 by Dr. George Denman, whose research concluded that a particular shade could be best represented by mixing 18% yellow ochre, 24% Venetian red (rosso cotto), 36% ivory black (carbon black), and 4% raw umber into a titanium white grounds. The school's present-day appearance retains much of this original color scheme, with only minor modifications.
The use of "old gold" as a color name in English first appeared in the early 19th century. Although the phrase "old gold" was originally written in reference to yellowish brass, the color name was soon transferred to yellow-orange alloys of gold with copper, zinc, or silver by the middle of the 19th century and eventually for pure golden-colored metals themselves.
The term "yellow" had also long been associated with gold; now it generally refers only to uncoated metallic gold (yellow metal). Old Gold (Optical Yellow) is closely related; it is more orange and obviously pastel (less bright).