Y just y

Could you walk on acid without taking damage?

I feel like yes bc RAW it says as if it were solid ground

If I was DM, I would great reduce the damage against you. I feel like parts of you would still touch the acid even if you don't submerge.

Does anyone know what "magical school" aura would come from this if a player cast the Detect Magic Spell on it? 

The Water Walk spell is Transmutation so I'd go with that.

Thank you! Sounds good to me 👍

While wearing this ring, you can stand on and move across any liquid surface as if it were solid ground.

Because not all classes can walk on water

Can you lay/sit down on a surface of water without being submerged? Or is it just walking specifically? 
What if the wearer is dead or unconscious? Would the magic still work?

how much do you think it weighs?

sorry it says stand specifically but ask your dm. the ring says nothing about conscious being needed but it would be hard to stay standing and be knocked out. I don't understand what magic has to do with it...

If any liquid acts as if it Were solid ground, then could you climb up a waterfall?

I would say no mainly because the water is rapidly moving and you still would have to deal with gravity. However if you have the ring work mainly like the spell you could put the ring on while under the waterfall and get magically launched to the top :3

What happens if you put the ring on when your underwater? Does it crush your body?

No. You shoot up to the surface of the water. As a "can" ability you also need to want to walk on the surface.

What happens if you fall off cliff wearing this ring? Do you fall into the water as normal, or does it act like you've fallen onto solid ground?

same as the water walk spell

well if you have spider climb you could try and run up it like its a escalator going down

Would this prevent you slipping on oil? If you treat the liquid as a solid surface, you should be able to just walk over any oil spill as if it didn't exist. 

A counter-argument would be that perhaps only the top surface feel solid, but it can slide over the oil - like putting a board on top of oil. But if that's true, the same could be said of walking on pure water. So my expectation would be that you treat any liquid as a solid surface and unless it is moving/flowing, that surface should 'feel' steady/fixed.