Work in a well-ventilated area and wear nitrile gloves and safety glasses. Resin fumes are harmful. Cover your work surface with silicone mats or baking paper.
Measure equal parts resin and hardener by volume into separate cups. Combine in a third cup and stir slowly for 3 minutes, scraping the sides and bottom. Avoid whipping in air bubbles.
Divide the mixed resin into smaller cups. Add a tiny amount of alcohol ink, mica powder, or glitter to each. Stir gently. Add pressed flowers, foil flakes, or other inclusions if desired.
Slowly pour the coloured resin into silicone jewellery moulds. Use a toothpick to move and swirl colours. Pop any surface bubbles by breathing on them gently or using a lighter briefly.
Leave to cure under a dust cover for 24–48 hours. Flex the silicone mould to release pieces. Sand any rough edges with 400-grit then 800-grit wet sandpaper. Add jump rings and jewellery findings to complete.