If it were just the jewel, or just the flower; heck, if it was only one symbol I would not even think twice. However they were all very popular items in the late 19th century.
The rumor that I always heard is that a member of SK transfered and missed her sisters. She found 7 friends that wanted to become SK. But for some reason SK couldn't expand at the time. So they started SSS. Seven Sorrowful Sisters. Only 7 of 8 were sorrowful because one was already SK.
But honestly, I put as much stock into it as the alleged meanings of KKG and Pi Phi.
I was told that SK has no records of any of the 8 SSS founders being in SK. But wouldn't taking the vows of another sorority be grounds for expulsion? Therefore, her name expunged from the records.