This depends on your desired type of jewelry, size, thickness and what you are mixing into it matters.
Here is a short doc I hope helps.
Use LIQUID DIAMONDS resin for the first layer. Liquid Diamonds is thinner and because of its lower viscosity, it is very easy to pour and to have it seep into nooks and crannies.
The Epoxy Resin Store
Phone: (951) 677-0400
Address: 540 Crane St suite A Lake Elsinore, CA 92530