Different cultures distinguish colours into different classes. You can do an experiment where you give a person sheet of randomly colored pages and ask them to divide them into named stacks.
A western civilisation member might do something like Red, Brown, Orange, Yellow, Green, Blue, Pink, Violet, Grey and perhaps do something special with White/Black. (11 basic colours)
A Russian will most likely split blue into light blue and dark blue. (12 basic colours)
Himba people have 5 basic colours:
Serandu – used to describe reds, browns, oranges and some yellows
Dambu – includes a variety of greens, reds, beige and yellows
Zuzu – used to described most dark colours, black, dark red, dark purple, dark blue, etc.
Vapa – used for some yellows and white
Buru – used to describe a collection of greens and blues
When I was a kid, it was "obvious" to me that dark green and light green were two completely different colors, and it frustrated me to no end that people wouldn't agree with me, yet insist that pink and red were different colors.
It’s a majorly weird thing. Knowing of a colour makes it obvious, but not having the concept embedded into your neurons means it isn’t split and out and distinguished when you experience the world. There are some African tribes with a very different knowledge of blue and green to us that makes the contrast very clear
And regardless, my point was more that "emerald" is clearly a worse analogue than "sky" for this particular color.