BeginnerSurvival
How to get, grow and ride a Happy Ghast in Minecraft
Soul sand valleys are the blue Nether biomes covered in Soul Sand and Soul Fire, and Ghasts spawn there often, so one trip covers both the fossils and the tears.
Tested 26.3

Soul Fire is a blue fire that burns on soul sand and soul soil and hurts more than normal fire.
It gives off light level 10.
Light soul sand or soul soil with Flint and Steel or a fire charge to get it. Unlike normal fire it never goes out on those blocks and never spreads, so it is a safe permanent decoration. It deals more damage than regular fire and scares piglins away.
This item has no crafting recipe.
Soul sand valleys are the blue Nether biomes covered in Soul Sand and Soul Fire, and Ghasts spawn there often, so one trip covers both the fossils and the tears.
It is a permanent blue fire for decor and piglin-proof bases.
Yes, light level 10.
No: when a piston pushes it, it breaks and drops as an item.