Gently heat the raspberries and sugar in a small saucepan. Let it simmer for 3-5 minutes until the raspberries and sugar melt together.
Take off the heat and let cool slightly. Stir in the chia seed and set aside to cool completely. The chia seed should swell and create a jam/jelly consistency.
Store in an airtight container in the refrigerator for up to 1 week.