I've featured concrete jewelry before (see links below). These designs are great if you have leftover concrete from hardscaping garden projects. Lana Red's "gold" leaf concrete pendant tutorial  on her blog, Lana Red Studio, has a neat embedded pin idea worth sharing.
She actually pushes a length of wire through her silicone mold before the concrete is added. Once set, that pin can be turned into a bail and it is not going anywhere!  Freshly mixed concrete is a lot more viscous than say liquid resin so the hole is not an issue.

Silicone molds are useful not just for concrete but for the popular resin and polymer clays.  You don't need heat for resin clay to cure. But if you use bakeable silicone molds, you can cure polymer clay in the oven!  Check out Ginger Davis Allman's instructions on using silicone molds.

Before You Go:

Original Post by THE BEADING GEM
Jewelry Making Tips - Wire JewelryTips  -Jewelry Business Tips