Badges weren't included in our dues but the cost of a plain silver or gold badge were told to us up front during recruitment. It is tradition in my chapter for the big to temporarily pass down her badge to her little until her badge comes in so that she can wear a badge after initiation since she'll most likely be so excited about getting to wear it. Most girls in my chapter got the plain gold or silver, a few opted for pearls, and very few got guards. I ordered a plain silver badge as well but a couple pledge sisters ordered more blinged out badges: sapphires with pearls, emeralds with pearls, etc. There are many options for ZTA badges (pink sapphires, diamonds, turquoise of course, opal, amethyst, rubies, emeralds). You can do the stones alternating or at the points or along with the whole thing and you can also do pearl, plain, or chased guards. I don't know of many rules about the badge other than how/where to wear it
I eventually got a badge on ebay (white gold with all pearls) and bought a silver guard and dangles to go with it. I'd love to find a white gold badge with emeralds and pearls since emerald is my birthday jewel.
