Random thought: Do sapphires ever need to talk to one another?

The short answer is yes.

The long answer is it depends on several factors.

Remember that, in Gem culture and society, things are predictable. Everyone conforms to a role.

Now this point is obvious, but let's throw in future vision. For sapphire's in Gem society, they can predict with almost 100% accuracy because things are predictable. Gems conform to roles, and virtually everything else can be accounted for.

On certain off chances, especially for incompetence or incredible will to defy the odds, future vision can be thwarted. It cannot be done reliably, hence why Ruby's act of saving sapphire led to an entire road of changes and thwarted destiny.

That's why, in Garnet's case, she says future vision is not 100%; she accounts for the fact that most of existence isn't as conforming and predictable as within and interacting with Gem society, and thus more paths present themselves.

Think of it this way: the number of future paths in Gem society is very small; most times the future is preordained because Gem's conform to strict standards. Outside of Gem society (including races that interact with it), things are more chaotic and less reliable, thus presenting more paths.

So when two Sapphires in Gem society interact, everything is laid out and they already know what is going to happen. For Sapphire's (like ours) that are outside of Gem society, things change and are less predictable.

By that logic, does sapphires even need to meet with one another?

I saw some interesting thoughts suggesting that two Sapphires might sort of short-circuit if they met each other -- both predicting too damn much in relation to each other that they freeze up. In that case, it's a good thing that they're so rare...!

Don't particularly buy that myself, but it's interesting to consider (even if they phrased it 34256% better than I'm doing, dammit why can't I find that post).

If it works the same as Garnet's future vision, then Sapphires only see an array of possible futures. While some futures are more likely than others, few of them would ever be completely certain.

Yes, because if would never meet they could never convey the information they would learn from the future vision.

Following rules of time, Sapphires need to talk to each other because they saw it in the future. If they didn't they would change the future and the conversation wouldn't happen. What's caused by the conversation wouldn't happen either.

Now since time travel hasn't been introduced in this show yet we don't have to go into paradoxes which would just make this more confusing.

EDIT: So since time travel has been introduced, lets get into paradoxes.

So let's say the conversation the Sapphires had caused one of them to use a time travel device to go back in time and they got stuck there. Later one in their life time they have the same conversation mentioned above with their younger self. Now if the younger Sapphire knew the conversation was coming but did not have the conversation, it would create a time paradox. That timeline would be destroyed.