Detect Kinship

You choose two creatures (one of them or both can be dead but for no more than 10 days) those you can see within range and gain knowledge if they are kins. If they are kin in no more than second generation, you learn how they are related.

As an option you can save information about somebody in a diamond (minimum 500 gp)

You can use the diamond instead of the creature. When you do this you spend the diamond.

 At Higher Levels. When you cast this spell using a spell slot of 6 level or higher, kinship that you detect can be more distant for 2 generation per level.