On another note, I'm not sure if hash is hashish (I don't think it is) but ive had hash oil many times and what happened it it got me super high. I didn't notice any bad properties to it besides I wanted to sleep and that I did for a while after smoking some of it on greenery.
I am sure hash is just a slang term for hashish, not sure about bad properties, I guess it all depends on how it is made, I remember the old "SoapBar" or "Slate" used to be terrible quality, but these days I think its all highgrade bubble hash its pure THC squashed in a block.
Soapbar bad yes but slate isnt that bad its basically just moroccan kief pressed into block, the main reason it isnt super strong is the THC content of the landraces used is very low compared to the high thc hybrids of today.
Also the grade of sieve used in the production of slate makes a difference as will the weather conditions/harvest of the year but in general slate is quite a clean product if the right grade of sieve is used, you may have heard of double zero which is named after the grade of sieve used in production.
A good Morrocan dry press or slate/flatpress can be really nice if you get the better end of the spectrum, a lot of people wrongly call it pollen and you dont need to burn it to crumble it, at the low end of the spectrum there is more plant matter in there and needs to be burnt to be crumbled.
SoapBar and the fake red/gold seals are all just repressed eurotrash with additives, slate tends to be with out additives (except the excess plant matter).
Oh and BTW its not pure THC pressed into block its the Trichomes/kief pressed into block Trichomes are not 100% thc.
https://www.harborsidehealthcenter.com/shop/concentrates.html