Yes, the auction result will be the key to understanding value...

Yes, the auction result will be the key to understanding value of Merlin and hopefully the company provides a lot of detail along with the price recieved. ie. we need to know the distribution of sizes/colours and prices attained for each. The link below gives wholsale pricing for fancy coloured diamonds which is the game Merlin is in. Note that brown/champagne diamonds are at the cheaper end with pink at the higher end. But interestingly bownish/pink is also at the higher end. The pictures in this announcement (to my eye) show light pink plus brown diamonds however, some may indeed be brownish pink.

http://www.ajediam.com/fancy_color_diamond_prices_5-00_to_5-99_carat.html

pricing above is for 5 carat, the average for all 22,000 diamonds is going to be below 1 carat i would think.