Random SU head cannon I found and want to dive into deeper:
What if where the gem is located on their body signifies part of their personality. Example Amethysts is on her chest because even when she doesn't show it, she's extremely compassionate and doesn't like it when something gets in the way of her loyalties with the Crystal Gems. Pearl's is on her forehead because she's intelligent and the smoothness of her gem means she's graceful and balanced. Garnet's are on the palm of her hands because she's strong and has quick reflexes. Jasper's is her nose because she quick to "sniff" out exactly what she wants when she wants. Am I making any sense or should I drop it?