First head- She's the leader of them both. She's doesn't trust other gems and will usually keep her distance if they come across one. If confronted however, she will attack and attempt to shatter them. She really doesn't have any moral thoughts when doing this as that's the first thing they experienced once emerged when found, so she's thinks acts before really thinking.

 When being alone with her twin, she's acts very sisterly to them. Just like any siblings they fight, but make up in the end pretty fast. If if she go the chance to be singular gem, she wouldn't take it despite saying sometimes when fighting. She's mostly grumpy. 

 Second head- She shy one who over thinks everything, but her twin keeps her grounded. While she untrusting of other gem too, she prefers the pacifist thinking. She doesn't like the shattering a gem and will attempt to stop her twin from doing so. She's more friendly and likes to experience things with a open mind. She does want to make friends,but's very conflicted. 

 When being alone with her twin, she's usually the one who cheers them both up. She's very cuddly and is  always attempting to cuddle with her twin when resting.

CC Zircon is a mentally strong gem,so she can’t poof from stress as much so when under certain strong emotions,she can change color.

 Head canon if a gem is mentally strong, they can keep up a physically form bit longer than your average gem when stress. She can still poof if not concentration enough however.

She can switch between few different pink/purple hues..

Example- Will add more soon

When not really feeling anything- Normal look(like above)

When stressed-  She turns deeper purple colour.