Color :
White diamonds color range from D (colorless, the purest white) to Z (light color).
D, E and F are colorless diamonds, G, H , I and J are near colorless , K and L are faint color, M to Z have a light color.
Emerald :
Emerald is a gemstone, a variety of beryl colored in green by trace amounts of chromium, vanadium and sometimes iron. Emerald frequently contain many inclusions, with a result of poor resistance to breakage making their cutting very difficult.
Yellow gold :
Yellow 18K gold is an alloy contianing 75% of pure gold, whereas 14K gold contains only 58,5% of pure gold.