Concise Bible Dictionary:

Purple Silk
A color often mentioned with blue and scarlet in connection with the tabernacle (Ex. 25:44And blue, and purple, and scarlet, and fine linen, and goats' hair, (Exodus 25:4), etc.). Among the spoils taken from the Midianites under Gideon was “purple raiment that was on the kings,” and it is used as a symbol of royalty (Judg. 8:2626And the weight of the golden earrings that he requested was a thousand and seven hundred shekels of gold; beside ornaments, and collars, and purple raiment that was on the kings of Midian, and beside the chains that were about their camels' necks. (Judges 8:26)). In derision the soldiers put a crown of thorns and a “purple” robe on the Lord, as king of the Jews (Mark 15:17,2017And they clothed him with purple, and platted a crown of thorns, and put it about his head, (Mark 15:17)
20And when they had mocked him, they took off the purple from him, and put his own clothes on him, and led him out to crucify him. (Mark 15:20)
; John 19:2,52And the soldiers platted a crown of thorns, and put it on his head, and they put on him a purple robe, (John 19:2)
5Then came Jesus forth, wearing the crown of thorns, and the purple robe. And Pilate saith unto them, Behold the man! (John 19:5)
). The rich man in Luke 16:1919There was a certain rich man, which was clothed in purple and fine linen, and fared sumptuously every day: (Luke 16:19) was clothed in purple; and papal Rome is seen as a woman clothed in purple and scarlet, royalty and splendor (Rev. 17:44And the woman was arrayed in purple and scarlet color, and decked with gold and precious stones and pearls, having a golden cup in her hand full of abominations and filthiness of her fornication: (Revelation 17:4); Rev. 18:12,1612The merchandise of gold, and silver, and precious stones, and of pearls, and fine linen, and purple, and silk, and scarlet, and all thyine wood, and all manner vessels of ivory, and all manner vessels of most precious wood, and of brass, and iron, and marble, (Revelation 18:12)
16And saying, Alas, alas, that great city, that was clothed in fine linen, and purple, and scarlet, and decked with gold, and precious stones, and pearls! (Revelation 18:16)