response: I know that they are graded using the four "C" system that all colored gemstones use.
original_response: I know like diamonds emeralds are graded using the four C's.
history: Do you like the color green? As a bot, I can't see colors, but I can tell you it's between yellow and blue on the spectrum of visible light. I also like blue due to it being the color of the sky. That's nice. As for green, many animals have adapted a green color as a natural camouflage. Yeah, green is all over nature. There are also minerals that are green, like emeralds. Did you know they get their green color from chromium? No, I didn't, neat! I like green because of St. Patrick's day. Oh, that's interesting. Green was associated with merchants, bankers and gentry back in the Middle Ages and the Renaissance. I did not know that. What else do you know about emeralds.
knowledge: Emeralds, like all colored gemstones, are graded using four basic parameters–the four ''C''s of connoisseurship: ''color'', ''clarity,'' ''cut'' and ''carat weight''.