“Pure” should modify words indicating color.
https://dictionary.cambridge.org/dictionary/english/pure
Then, I wonder, for example, to express pureness of blue of the ocean, “pureness of the ocean” doesn’t work, and only “pureness of blue” works.
“Pure” should modify words indicating color.
https://dictionary.cambridge.org/dictionary/english/pure
Then, I wonder, for example, to express pureness of blue of the ocean, “pureness of the ocean” doesn’t work, and only “pureness of blue” works.
Pure can modify words indicting that it is not mixed with something else
"Pure cotton" "pure water"
Particularly, not mixed with something harmful
"Pure air"
And it can be metaphorical
"pure horror", "pure hell"
When it is applied to a colour word, it means an unmixed and intense form of that colour
"pure white" (#FFFFFF the colour of snow) "pure black" (#000000 the colour of soot) "pure blue" (probably the colour of ultramarine paint, although this one is more ambiguous, in HTML terms it is #0000FF)
"The ocean" is not a colour word, so "pureness (or purity?) of the ocean" would refer probably to sense 1 or 2 (not mixed with anything harmful) or perhaps sense 3 (a metaphor for the effect of the ocean on your spirit?)