Phi Gamma Delta actually has an interesting page on its website that chronicles the changes made to the badge design from the founders to present day. Its been all over th map, from the simple design of 1848, to heavily jeweled versions in the late 1800's, to a very small one in the early 1900's. To promote equality among the brothers, jeweled badges were outlawed around the turn of the century.
Today's badge (since 1923) is identical and size, shape, and design to the original badge conceived by the founders in 1848. Balfour actually took a founders badge out of the archives and took a mold of it, to insure a match to the original. The whole story appears here:
http://www.phigam.org/history/Headquarters/exhibits.htm
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