Emerald has many special qualities, but coloured stone professionals generally agree that emeralds are most of all, about colour. Subtle variations make significant differences in value. COLOUR IS THE MOST IMPORTANT QUALITY FACTOR FOR EMERALD The most desirable emerald colours are bluish green to pure green, with vivid colour saturation and tone that’s not too dark. This perfect colour balance makes Colombian and Brazilian emeralds in particular so popular. The most-prized em