halo 3 skull question?

[bill]

ok well i have all the skulls on my main profile and im trying to get them all on my other, and it says i have about 6 skulls on the skull select screen but i didnt get the achievement for like 2 or 3 of them....

 

[Matt]

email bungie

 

[Matt]

email bungie

 

[CAJ]

Some of them are classed as Silver Skulls (Easier to Find) and they do not give achievements. They are the bottoms rows in the select screen.

Only the harder, gold skulls (top rows) give achievements!