That's quartzite, but it's what I call a 'grainy' quartzite, meaning that it's been subjected to a moderate level of metamorphism. Etching won't be a problem, because it's made of quartz, but porosity may be a concern because it's not as tightly fused together as a quartzite like Taj Mahal or Fusion.

Many more details here: https://usenaturalstone.org/properties-of-quartzite/

Looks like quartzite! It’s beautiful! Good luck!

That's a nice slab!

@karin_mt Thanks for the feedback and link to the article. I’ve read it before, but it makes a lot more sense now that I’m actually considering quartzites for our house and looking at the different options (before I was more focused in the marble versus quartzite debate). I’m actually finding this whole process of trying to understand natural stones, their characteristics, and their attributes fascinating. I actually drug my husband to the stone yard on our last date because I just thought it would be fun to ohh and aww over the different stones together. Would you mind weighing in on a couple more slabs and explaining what you see that helps you determine where on that sandstone/quartzite spectrum they fall?

@Barbara beautiful countertops! I posted a another picture above of a slab of Gray Cayman that looks a lot like yours too. Does yours have some blue in it it? I’d love to find one with a hint of blue and the platinum I posted seems to have a little (I’m going to go and try to see it in better light again today). The edge staining issues is my big concern. Like you said, I don’t think I’d notice small stains throughput the countertop because of the variation. However, if the entire edge starting turning dark, that would bother me, especially since the quartzite costs so much more. Have you had any problems like that? What sealer did you use?

My fabricator used Dry Treat Stain Proof. I’ve not had any bleeding. Before I chose him I actually showed him all the horror pictures from Houzz and he knew what they were and how they had happened. Also important to use a non staining adhesive. I definitely have some blue, part of why I love it, but kind of a moody blue, not a baby blue. Here’s a closer photo next to some wallpaper I’m considering. I had seen a slab similar to the lighter one you posted but to me it felt more baby blue and also I was concerned about any stains being more apparent on the lighter background. So far with the sealer I have no stains or etches, and have definitely found food drips the next morning. I do think it is inevitable but won’t show up as much on this background.

Don't overlook the porosity please. How do you make a seal between the sink flange and the stone bottom if you don't know if the stone bleeds?

All three of those are in the same category of "grainy" quartzites. They all still have telltale signatures of their youthful days as sedimentary rocks: the cross beds and layering.

The cross bedding and color on the last one are perfectly evocative of breaking waves. It's beautiful!

Joe makes a great point about the adhesive - that's another place that the porosity problem is showing up. Be absolutely sure that your fabricator has heard of these problems and knows exactly what to do to avoid them.

@Barbara thanks again. Your quartzite is so beautiful and I‘m glad to hear you haven’t had any issues. I also really like the wall paper you are considering. Unfortunately, they don’t have enough slabs of the Platinum for my kitchen, so that leaves the other ones I posted as contenders.

@Joseph Corlett, LLC I appreciate your feedback. I talked to my fabricator about the horror stories I have heard about. She was familiar with them, but they’ve never had an issue. She did say they try to prevent them by making sure to use the correct silicone, sealing inside of cut edges, sealing the back of the slab, waiting for the slab to dry between fabrication and sealing, etc. So it sounds like they are a quality fabricator and know what they are doing....I hope!

@karin_mt thanks again for chiming in with your expertise. I’m so grateful you are willing to contribute to the knowledge on this group.

I'd have your fabricator mock up a built-up edge (if you're using one) and mock up a silicone or other gasketing method before taking the plunge. Let them sit for a month or so.

Because your fabricator has never had a problem is irrelevant. The sun has risen every morning for billions of years, but that doesn't make it logical.