Veyr nicely done! Are the shells chocolate?

The shells are fondant pressed in a chocolate mould, (mold).

how did you make the gold trim?

I used a product called "cake decorators edible paint" which I bought from my local cake decorating supply store. It looks like nail varnish in a bottle and I painted it on the fondant.

i love your treasure chest,could you please give me instarction

I cut a 10" square cake in half to create the chest and the lid. For the lid I just carved the sides off to give it a rounded look. The lid is on a thin board and is supported by dowel in the base, shorter at the back and taller at the front so that it is open. the whole cake is covered in buttercream, then in chocolate fondant. (oh, do the lid and the base separately and then place it on top with fondant 'hinges' to cover any mess at the back. The chocolate foil coins are stuck in place with royal ic...

cont... royal icing. The sand is brown sugar and the shells are fondant. Hope that helps! :)