His eyes were not the color of the sea, no the sea was too unspecific in color to use as a descriptor. There were some oceans that didn’t seem blue at all, and the color of blue varied depending on the pollution, time of day, minerals, and many other factors. It was not the Earth's sky either. Spock had seen it many times but it was not this particular shade either.
Perhaps some kind of jewel or crystal, yet sapphires were too dark. Blue aventurine was closer, yet not quite the same, neither was blue agate. Spock had even searched for a list of crystals that were blue and all disappointed.
A robin's eggs were very blue but not quite the same shade, nor did they have the glow to them that Jim’s eyes seemed to possess.
It could be closer to Uranus, it would be quite fitting for Jim’s eyes to match that of a planet as the man was born to be in space.
There was also an endless amount of fauna and flora that were blue on various planets, yet none were as stunning and captivating. It was truly frustrating, however, he knew there must be something out there in the same shade. It was highly improbable Jim could be the only one with this shade, this blue that held Spock captivated whenever their eyes met.
It is what Spock convinced himself of, the reason he could not drag his gaze away from the man. It was pure scientific curiosity to study the man as he bit the bottom of his stylus, eyes focused on the padd in his hands. Or when they would play chess and his eyes would somehow alight when he knew he’d won or had a chance to.
He simply was cataloging every shade he could see in various lightings. It didn’t matter if he’d seen his eyes in the lighting many times before. It was easy to believe the human saying that the eyes were the gateway to the soul when Jim’s looked like that.
Spock thought of his own plain brown eyes, the color of soil, tree bark, an animal's fur, rock, and silt. Nothing like Jim’s. His was lighter than Vulcan’s, he had human eyes, he knew that. His mother had the same brown eyes and yet hers were more alive, more vibrant. They shined as she read something particularly interesting or Spock said something that would have made her laugh had she not lived on Vulcan for so long. He almost wished it hadn’t changed her.
Sometimes she had let her humanness through, the way she’d turn on music and dance to it while cooking, or the stories she’d read to Spock. He is honored to have her eyes even when it meant being bullied or teased. He would always have that reminder of her.
Did George Kirk have the same blue as Jim? It was hard to believe anyone else could, but colors are genetic. Jim must have got it from someone. Spock had seen a picture of Jim’s mother and while her eyes were blue they were not the same, not as vibrant.
Spock stared at Jim sometimes, too much he knew, but no one had called him out on it as of yet. How could he stop when those were the eyes he pictured when he thought of beauty, empathy, forgiveness, and braveness? When he imagined fifty years from now so much would change but not those eyes, they’d always stay the same. The same eyes he imagined staring into during his time whenever it came.
Spock may not know anything in the universe with the same color or vivacity, but he would have a lifetime to ponder it.