Ruby had always been hot headed. Always rushing into things. It seemed to be a trait of rubies, just as many gems of the same type had common traits. Jaspers were brash, bold warriors, zoisite's were skilled tool makers, peridot's were good for technological issues, scapolite's were excellent for entertainment, pearl's were good for storage, thulite's were good record keepers, pyrite's were exceptional excavators – everyone had their place. Rubies were fiery small fighters – their red color only serving to reinforce the fire within.
Sapphires were calm and collected – very much an exact opposite of a ruby. It wasn't often that the two worked together, due to their conflicting personalities. The one thing that could make the two a powerful team was there where one had a weakness, the other seemed to fill in the gaps perfectly. Although a ruby's instinct to run into things often negated the exemplary planning and strategy that a sapphire offered.
So it was odd that Ruby and Sapphire would have met at all. And yet, for some reason, this Ruby was willing to work in cooperation with a Sapphire – most of the time. More often than any other Ruby. Perhaps it was their similarly placed gemstones. While Sapphire's lay on her right, Ruby's lay on her left. In humans, the right side of the brain controls the left side of the body, while the left side of the brain controls the right side of the body. The right brain commonly makes decisions based on emotions and subjective information, while the left brain is more likely examine the objective, logical, and analytical aspects of a scenario before taking action.
Perhaps this bit of right brain/left brain science drew Ruby and Sapphire to each other. In a way they would not admit while on Homeworld, they completed each other – right brain and left brain. Left hand and right hand.
Both struggled with patience with each other. Ruby wanted to be patient, and slow, because that's how Sapphire was. It was very difficult at first, as she was denying her natural instincts. But when she was calm, Sapphire wanted to be around her more often, and that pleased Ruby immensely. She was always trying to better herself for Sapphire's sake. If she could make Sapphire happy, then she was happy, even if she couldn't do things in the way she preferred.
Though one of Sapphire's default emotions was patience, with Ruby it could be difficult. She often didn't think before taking action, which led to herself getting injured, someone else getting injured, or something breaking because she hadn't been careful. But who was Sapphire to try to change who Ruby was? Even though Ruby made mistakes all the time, for some reason she never did stop doing things without considering the future consequences. And yet, she didn't seem to be frustrated by all the mistakes she made. She just kept going, moving on to the next task even if she'd horribly failed the previous.
Sapphire was always so careful to use her future vision to look into the future, to avoid making mistakes herself. She had noticed that Ruby seemed to calm down the more they spent time together. She'd pause, ever so slightly, examining a situation before diving into a task. It was subtle, but Sapphire was very detail oriented. Where Ruby used to rush forward, now she took but a moment to look back and forth. She avoided running into gems and getting hit by transports a lot more often nowadays. Of course, Sapphire knew if she were to bring it up, that Ruby would deny it and likely go back to her old habits to show Sapphire that she hadn't changed.
And yet, though this was seen as a positive change by the two, it was also dangerous. Different types of gems were expected to behave in specific ways. Even if those ways were not the most effective, there was a normality that all followed. No one questioned their role in society. Their gemstone determined that. But were rubies always so reckless? Or had they merely been following suit of their fellow rubies, who thousands of years ago were trained to act a certain way?
If one ruby could change, could break the mold that was expected, did that mean other rubies could? Did that mean other gems could? Those that did not follow the standard were considered defective and useless. But were free-thinkers really broken, or did they merely express an interest in questioning the status quo?
So though it may not have been obvious to an outside observer, Ruby and Sapphire caused subtle changes in each other's behavior. Of course, once Sapphire left, all that was reversed in Ruby. When Sapphire had come along, Ruby had something more to live for than herself, a reason to care about her survival and the continued preservation of her gem. With Sapphire gone, Ruby fell back into her impulsive temperament. Sapphire, on the other hand, became more absorbed with analyzing the future, rather than living in the present. It was likely this that led to her endangerment on the battlefield.