What is the significance of blue in Judaism? Are there other special colors?
In his analysis of the meaning of the mitzvah of tzitzis (tassles placed on the corners of a four cornered garment), and in particular the thread of blue that one is supposed to place around it, R’ Samson Refa’el Hirsch (Frankfurt-am-Main, Germany, 19th cent) writes (in Collected Writings vol III pg. 126): We find only three terms to encompass the colors of the spectrum: adom for red, yaroq for yellow and green, and techeiles for blue and violet Red is the least refracted ray; it is the closest to the unbroken ray of light that is directly absorbed by matter. Red is light in its first fusion with the terrestrial element: adom, related to adamah [footstool, earth as man’s footstool]. Is this not again man, the image of G-d as reflected in physical, earthly matter: “vatichsareihu me’at mi’Elokim” (Tehillim. 8,6)? The next part of the spectrum is yellow-green: yaroq. Blue-violet is at the end of the spectrum: techeiles. The spectrum visible to our eye ends with the violet ray, techeiles,