The woman’s suffrage movement was very conscious of its public image and carefully crafted this image to communicate its messages and reach supporters. In the United States, purple, gold and white were the colors of the movement.
The use of gold goes back to 1867 when Kansas was considering passage of a state suffrage referendum. Eizabeth Cady Stanton and Susan B. Anthony adopted the sunflower, the Kansas state flower, as a symbol of the suffrage cause. Soon, gold pins, ribbons and sashes as well as yellow flowers became symbols of the cause.
The Suffragist (Vol. I, No. 4) published on December 6, 1913, described the symbolism of the colors:
“Purple is the color of loyalty, constancy to purpose, steadfastness to a cause. White, the emblem of purity, symbolizes the quality of our purpose; and gold, the color of light and life, is the torch that guides our purpose, pure and unswerving.”
More here – https://www.nps.gov/articles/symbols-of-the-women-s-suffrage-movement.htm