So, we have an answer from Pathal the theorycrafting hero from the Elistist Jerks forum about rogue stats. Vishas and me will work them into the guide soon. Remember these are heroic T14 numbers, not yet specialized on players.

Also remember: PvP Power and secondary stats have double the amounts than primary stats.

Assassination stat table  
Agility 2.7288
PvP Power:    2.2856 
Yellow Hit Rating 1.8504
Mastery Rating   1.3373
Expertise Rating 1.1302   
Haste Rating 1.0777
Crit Rating 0.9973
White Hit Rating 0.6658

Combat stat table
Agility    2.77
Yellow Hit Rating    2.4953
PvP Power:   2.4664
Expertise Rating    2.3198
Haste Rating 1.6345
Mastery Rating 1.1867
Crit Rating    1.0759
White Hit Rating    0.9348

Subtlety stat table
Agility 3.676
PvP Power: 3.092
Yellow Hit Rating 1.5306
Haste Rating   1.314
Expertise Rating 1.2664
Mastery Rating    1.1916
Crit Rating   1.1857
White Hit Rating   0.8136


How the calculation works
Use the number of stats * the number from the stat table to see how much they are worth in a socket. For example shoulders for Assasination:

Socket bonus is 60 Agility: 60 * 2.7288 = 163,728

Mastery/PvP Power gem is: (160 * 1.3373) + (160 * 2.2856) = 213,968 + 365, 696 = 579,664

PvP Power gem is: (320 * 2.2856) = 731,392

Pure agility gem is: (160 * 2.7288) = 436,008

Now with the socket bonus added:

Green PvP Power / Mastery: 743,392
Blue PvP Power: 731,392
Red: Agility: 436,008

Means it's best to use a green PvP Power / Mastery gem for the shoulder slot when playing Assasination. I guess you get how the math works, if not we will try to make it more clear.