Sort the blackberries and boil with 1/8 litre water for 10-15 minutes. Then put the blackberries in a pointed sieve and collect the juice in a bowl. Let it cool down a little. Score the nectarines crosswise, place them on a plate and cover with microwave foil. Heat at 700 watts for 2 - 2 1/2 minutes (or blanch with hot water).
Rinse nectarines cold and remove skin. Halve the fruit, remove the stones and cut the flesh into small pieces. Put apricots, jam sugar and citric acid in a pot. Cut the vanilla pod lengthwise and scrape out the pulp. Measure out 1/2 litre of the blackberry juice and pour it into the pot as well. Mix everything and bring to the boil. Let it boil for 1 minute. Test the jelly (put some jam on a saucer). Pour the hot jam into the prepared jars using a preserving ring.
Measure out 1/2 litre of the blackberry juice and pour it into the pot as well. Mix everything and bring to the boil. Let it boil for 1 minute. Test the jelly (put some jam on a saucer). Pour the hot jam into the prepared jars using a preserving ring. Close with moistened cellophane and tie up