To get this trophy very quickly with no effort, you can activate the debug mode to select the special stages.
At the title screen press quickly:
,
,
,
,
,
,
,
,
,
,
, hold
+
.
Then select "special stage" and enter it while holding
+
.
Press
to turn your character into a ring, move directly to the "chaos emerald" and press
again to collect it.
At the score screen, press
to pause the game and press
. This will unpause and take you back to the title screen.
Press
+
to go back to the stage select and
+
again to get straight into the "special stage", which is already highlighted.
This time, you'll play the 2nd special stage.
Do that for all 6 "emeralds" and you'll collect all in no time.