Blue Pearl's Links
Pearl adores and idolizes Aqua, formerly to the point of being so subservient as to do whatever she wishes (as pearls are "supposed" to do). She is quick to forgive and make excuses for Aqua. When they are reunited at Little Homeschool, she recognizes that Aqua has grown a lot and Pearl is very supportive, knowing "she had it in her to be great. she had it in her all along even when she didn't know it", but this is perhaps unhealthy as she has to learn to exist for herself, too. Fortunately, she is able to be more independent since both gems have somewhat moved on. They have a cordial relationship but there is a bit of awkwardness all the same.
Aqua had a pearl made for her when resources were more abundant on Homeworld, and she would boast about it- but not in front of the pearl- to everybody, as if it was a sign that she was, well, more important than she actually was. Her pearl adored Aqua and looked up to her, and Aqua appreciated the praise and adoration because it only confirmed to her that Aqua was awesome. The pearl was the one gem Aqua (relatively) cared about, in the sense that Aqua appreciated and enjoyed her company and flattery, but Aqua, being a Homeworld gem, didn't think of the Pearl as particularly an equal. Still, Aquamarine enjoyed showing off to all the same. (this relationship was honestly inspired by Scootaloo's idolization of Rainbow Dash, and Rainbow Dash's arrogant side in general, if that gives a better idea of what I'm going for.)