The method is, ironically, not abstruse
Throughout much of Diablo 4, your progression will feel remarkably straightforward. Defeat monsters, collect loot, and equip things that make your numbers go higher. That said, this will become much more complicated once you get into creating your perfect equipment.
For example, if you’ve tried to use Imprint Aspects on a piece of jewelry, you might need Abstruse Sigils to complete the job. In truth, these work similarly to Baleful Fragments, which you can learn about here. However, if you just want the quick and easy answer on where to find these, we have you covered.
Where to find Abstruse Sigils
Abstruse Sigils come from salvaging Legendary jewlery. In the case of Diablo 4, “jewelry” includes amulets and rings. That said, I can’t stress enough that salvaging Legendary jewelry only offers a chance at getting an Abstruse Sigil. You’re not guaranteed to see one when salvaging, so you might want to hold on to certain pieces you have other uses for.
From my experience, item level appears to influence the drop rate of Abstruse Sigils when salvaging. I haven’t gotten any rare drops from legendary equipment at lower levels, while gear in the level 35+ range seems to do it for me. After investigating the wider community, I couldn’t find a firm source on how the drop rates for Legendary jewelry work. As a result, I’d recommend finding other uses for low-level Legendary gear and saving the salvaging for stronger gear.
You should also remember that Abstruse Sigils come exclusively from jewlery. Legendary armor may drop Coiling Wards, and weapons will yield Baleful Fragments (as mentioned above). While you may want these materials as well, don’t blow through these equipment types hoping for Abstruse Sigils. You’ll just wind up disappointed in the end.
We’ll keep you posted as we learn more about Abstruse Sigils. For now, just take legendary jewelry you don’t need to the Blacksmith and hope for the best. Good luck perfecting your equipment!