"Solid Like Stone" vs "Solid Like A Stone", which one would you prefer?

Question

I found both forms (with and without "a") on the Internet. I don't know which one is more acceptable.

Is it an idiom?

https://wolfstone.za.com/blog/1-solid-like-stone-to-stone-like-solid

https://seekingalpha.com/article/2095473-suncor-energy-solid-like-a-stone

Answer 1

As this Ngram graph shows, neither expression is particularly common: in my opinion, neither is idiomatic either.

Reading the full text of the two articles, there are sufficient grammatical errors to make me doubt that the author or either article is a native English speaker.

There are two similar idiomatic expressions: "as solid as a rock" occurs more frequently, and "rock solid" is very common.

Note that there are differences between British and American English in the use of the words rock and stone.

Answer 2

Both are correct.

solid like stone (stone - mass noun)

solid like a stone (stone - countable noun)

[ (as) solid as a rock= having a very strong basis, strongly built (not likely to break/fall) ]