Do you think there is any significance of the star being blue on a white background? It's from the mid-19th century
There is much about the gematria and geometry of the star that is ancient, but I have not run across anything ancient about the colors.
The earliest claim I have found regards a 19th century ʝʊdɛօ-Zionist poet von Frankl who claimed in a poem that blue and white were "Judah's colors."
If you or anyone else find something earlier, I'd be interested to know of it. The Star of Rempham flag has appeared in different shades of blue… sky blue, dark blue, cyan, etc., so I would be surprised if there was any legitimate ancient lineage to the variety of colors. If I was a betting man, I'd bet that the colors were like so many things Jєωιѕн, a bunch of made-up manure.