Seating area around outdoor fireplace. Crushed gravel or pea stone?

The larger the stones.... the harder to get things to set level... and the more uncomfortable they are to sit or rest your feet on.... decomposed granite or pea stones/gravel compact better...... and FYI... I saw a new thing on one of the DIY channel shows.... it was called a "gravel grid"(google search it) it opens up into "cells" like a honey comb.... and helps to keep gravel, etc. from migrating.

I used a layer of sand then a layer of crushed rock then another layer of sand inside the pit and outside

Use pea gravel because you can easily walk over pea gravel and it looks good.and you can also use pea stone with crushed gravel and for further help you can check gravel-calculator/ here are different options with explanation it solve your problem easily