Gem rarity question

[Exonesia]

Asides from having an increased number of stats, what is the difference between a sparkling pentagon gem (say diamond) versus a brilliant hexagonal gem?

[Flareon]

takes more to craft em and you get more from dismantling them. 

[Exonesia]

i was wondering more of from a usage perspective; which one would be better;

 

Is it as simple as it seems where brilliant hexagonal (example: 490 block) just outright beats the sparkling pentagonal (400 block)? are there any other underlying factors behind gems like proc rates or that stuff?

[Flareon]

higher rarity are just better, there isn't really proc rates since most have instances to proc. 

[Exonesia]

higher rarity for the same gem would definitely be better, but if comparing a sparkling 5-side gem with a brilliant 6-side gem, the higher shape gem would be better in this case? 

[Flareon]

Pentagonal > Square > Triangle

 

More sides = better.