First, wash the apricots, pit them and cut them into small pieces. Mix apricots with lemon juice and preserving sugar and let stand for about 2 hours.
Bring apricots to a simmer over low heat and simmer, stirring constantly, until fruit is soft and falling apart.
When fruit is soft, bring jam to a boil and simmer until bubbly, about 7 minutes.
Make jelly test, fill apricot jam sterilely into hot rinsed jars.
Put some alcohol on the lid, light it and close the jars with it.