I have always seen Shadow Storm classified as a quartzite, not a granite, nor a marble. However, even as a quartzite that doesn't mean it won't etch. Get a sample of this stone, and drop some lemon on it, and see if it etches. I have granite counters, and have accidentally left salad dressing drips (with vinegar in it), wine spills, and similar on my counters all night, with no etches or stains. That is a dense granite.

Your pictured slab is breathtaking - but you must get a small sample, and test it. Or, even if it does etch, you could decide "this stone is gorgeous, and I don't care about the etches".

It’s marble and has always been marble. Despite the mislabelers having their way with creative writing.

It’s quartzite

It’s marble

Some people feel more comfortable with being able to label things. The bottom line is that it doesn’t matter what the OP’s pictured stone is labeled. What matters is how the OP feels about the beauty of the stone and whether that supercedes her feelings about etching. Do you know how many people on this forum have professed their love for their marble kitchen counters with etches galore? I’ve been reading their enthusiastic posts here for years. I myself don’t like etching, but that’s me. Everyone feels differently.

The OP asked about testing. This article from Karin_mt is a must-read.

Edited to add: forgot the link - here it is:

http://usenaturalstone.org/definitive-guide-quartzite/

My shadow storm was sold to me as a marble. It will be installed in about 3 weeks. I know it will etch but I'm not worried about that.

This pattern seems to be less likely to show etching than a more solid color...however if it is a shiny finish ...and etching dulls the finish...that may be more obvious than other types...