The Scarab cards have gold edges.
These are the cards which HAVE to be removed from the board in order to pass the level.
Here the King and Queen are scarab cards.
When you clear the Scarab cards some Scarab beetles crawl into their hole and give you a YELLOW gem.
However, others will run around the board before they crawl into their hole.
These ones carry different coloured gems,
either BLUE or GREEN.
If you click on these scarabs BEFORE they crawl into the hole you will get whatever coloured jewel they are carrying
PLUS 1000 points!
Most levels will give at least one or two running Scarabs so it's always a good idea to try to catch them if you can.