From the website:
History of The Quill
The Founders of Alpha Xi Delta gave much thought to the selection of an emblem that would symbolize the ideals of their new fraternity. The original Quill badges, smaller than they are today, were approximately seven-eighth of an inch long and were set on stickpins. Founder Lewie Strong Taylor designed the original stickpin Quill, which is on display at Fraternity Headquarters. The stickpins were later changed to clasp pins.
The first jeweled Quill was made for Cora Bollinger Block. It was set with three jewels in the shaft, a sapphire flanked on each side with a turquoise. During the early years, the badges varied slightly from each other in size, shape of feathers and choice of jewels. A few early badges were made with the initials in black enamel instead of burnished gold.
In 1911, a definite die was chosen for the official badge, and the choice of jewels was limited to pearls and diamonds. The Quill badge is a conventionalized quill of gold with the letters raised and burnished gold on the barbs of the feathers.
ETA: I just recently found out we can have our pearls replaced with diamonds...supposedly the nat'l president's Quill has all diamonds. I'd love to do that one day...when I can afford it!
Threaded Mode