Here's how to read and understand this Price Guide... every gem graded with the GIA Gemset will have a Hue, Tone, & Saturation rating, as well as a Clarity rating. Using the Hue, Tone, & Saturation Numbers on the Gem Report, match the Hue, then match the Tone, & Saturation Numbers in the "Exceptional", "Very Good", or "Good" columns. This will tell you the overall Color Grade. Next using the Clarity Rating on the Gem Report, find the Price Chart having the same Clarity Rating, then match the Carat Weight of the gem with the applicable Color Grade column to arrive at the retail price per carat.
NOTE: all prices are per carat, so you need to multiply the price per carat to the carat weight of the gem (ie: a Golden Yellow Sapphire that is 4.50 carats, "yO" hue, "Exceptional" tone and saturation, and "VVS" clarity, is priced at $1,000 to $1,150 per carat, so the total Retail price would be 4.5 x $1,000 = $4,500 on the low side, and 4.5 x $1,150 = $5,175 on the high side of the Retail price).