I've heard this theory many times and have many questions about it, but I'm not a scholar of antiquity. How do we know the Egyptians had a word for blue, if th

I've heard this theory many times and have many questions about it, but I'm not a scholar of antiquity. How do we know the Egyptians had a word for blue, if the Greeks didn't? What did everyone call the dyes and carvings made Lapis Lazuli? And what about dyes produced from woad and indigo? How did people describe the color of sapphires?