This is just my theory, nothing special. Maybe. This is my idea of who the statue of the gem is outside the Temple. I know that she must be a fusion, because of her multiple arms, and gems in there respective places. In most episode's title card, you see the Gem's palm, with a gem on it. I think that gem must be moonstone or sunstone. I think this because the sun and the moon is always shining on it in the title cards.
The gem's shape is also an oval shape, in which moonstone and sunstone is fashioned in sometimes. I will upload pictures later. Also, in one title card, it seems that the gem seems to be emitting some type of blue sparkle, at night. Possibly stars.
I will be adding more to this once I have gotten more information feel free to comment your ideas and opinions, but don't be too harsh as I know myself that this is not a very logical theory. Deuces ;)