they are some sort of agents/spies/whatever for white diamond and work together
their relationship is best described as siblings in human terms (twins who annoy each other but also care about each other a lot)
the headphone things connect their thoughts so they can use telepathy with each other (it’s irritating)
this means they can easily finish each other’s sentences etc.
they are nearly always together, but usually not fused
tanzanite 2 (longer hair) is insecure with an inferiority complex, while tanzanite 1 is arrogant and narcissistic with a superiority complex. both are equally bitchy, violent and snobby
2 has issues with individuality and often feels like just an accessory / fusing partner for the more confident 1. she often worries about disappointing her
2 likes fusing with 1 because she feels better about herself while fused, but 1 feels irritated by the emotional baggage. she likes the power of being fused, though, so she’ll gladly do it regardless (plus they need it for some of their missions)
both are very pro-homeworld and share some traumatic experiences with rebels