The greek could see "blue" but associated it with other external and internal phenomena....
And seing a color is not only seeing something external but translating it physiologically and interpretating it.....
Then our "blue" is not their "blue".....The lack of the word"blue" is a sign they associate this color with other impactful phenomena then they did mever feel the need to detach it from these phenomena and name the "blue" abstractly with a specific word refering only to colors like they did for others colors... Probably the physical color blue impact then very much , so much, that it was not only a "color" but a more powerful phenomenon ....
By the way you can interpret turquoise like a green shade not a blue shade....
This is my explanation...
But i am not a specialist for sure....
And seing a color is not only seeing something external but translating it physiologically and interpretating it.....
Then our "blue" is not their "blue".....The lack of the word"blue" is a sign they associate this color with other impactful phenomena then they did mever feel the need to detach it from these phenomena and name the "blue" abstractly with a specific word refering only to colors like they did for others colors... Probably the physical color blue impact then very much , so much, that it was not only a "color" but a more powerful phenomenon ....
By the way you can interpret turquoise like a green shade not a blue shade....
This is my explanation...
But i am not a specialist for sure....