I'm just guessing here, but I'd guess that the resin makes a big difference. Both quartz and granite are crystalline. A scratch would be where you could scrape some crystals off. The resin holds the quartz crystals in place, while there's no goop holding the granite crystals. You might try a diamond blade on both, as a follow-up. :)

Sorry Blondelle -

Not tryin to bust your chops here... but....
I am going to have to..... go ahead and......
disagree with you on the
"Quartz counters are harder than Granite" statement -

Remember who is making that claim - the Quartz producers.....

The fact of the matter is this:

Quartz crystals are in the same range of hardness (as tested on the MOHS
hardness scale) as components of Granite (which are primarily Feldspar,
Micah and QUARTZ)....

The resins that bind the quartz crystals together in Quartz products (polyesters)
are much softer than most of the geological components of Granite..

I work with both products, and they are BOTH GOOD PRODUCTS, so I am
NOT trying to dissuade anyone from using one or the other. BOTH products
have great benefits, and likewise - each have their drawbacks - the end user
has to decide which qualities are most important to them....

Just remember that the claims that any producer makes about their product
are just that - claims. Facts on the other hand - sometimes get omitted when
a sale can be made - on EITHER product.

hth

kevin

Diamond will scratch diamond. Does that mean that diamond is harder than diamond?

Any material will scratch itself. Quartz will scratch quartz and granite will scratch granite. And granite will also scratch quartz and quartz will scratch granite. That doesn't mean one is "harder" than the other.

What you should experiment with are everyday kitchen objects like knives, coffee cups, pots and pans. I'm sure you will find that these objects will scratch neither surface when used in normal kitchen.

I have a quartz countertop, but I have to say that the experiment really doesn't seem to have that much meaning to me when choosing a countertop. I would start with what you are drawn to in terms of aesthetics, because it is something that you see and work with constantly in the kitchen. How do you feel when you see a gorgeous piece of nature made granite? Are you a marble-lover? Do you like the industrial feel of stainless steel countertops? Is your plan for your kitchen modern, traditional, farm-house, etc...
There are so many great choices for a countertop, that compare to each other fairly well. It may come down to a detail or two that makes one a better choice for you than another, but start with what you love!!!! Granite has sooo many characteristics that make it a great countertop, but it is not quartz and visa-versa.

At least part of the issue is in what the stone industry refers to as 'granite.'

Many type are NOT granite, but any one of a number of other stones, often of varying hardness.

The 'quartz' counters (actually sand in a binder) depend on the binder for their scratch resistance.
If you go after them with a material stronger than the binder you will introduce scratches by removal of the quartz.
The material does not have to be harder than the quartz, just strong enough to pop the quartz lose from the binder.

"Any material will scratch itself. Quartz will scratch quartz and granite will scratch granite."

Yes, well my point is it didn't. The quartz didn't scratch another piece of the same quartz but it did scratch the granite samples. I wasn't going by the vendors claims as I stated I didn't believe them. All I'm saying that I tested them for myself and the granites scratched and the quartz didn't. I think everyone should test everything themselves, but I was surprised at the results when I did.

I'm not trying to defend the quartz industry. Just making my own observations!

I find tom cordovas site also try's to educate people about this very subject:
http://tomcordova.com/
I've learned a lot from this forum and from reading his website.

"The quartz didn't scratch another piece of the same quartz but it did scratch the granite samples."

How do you think grinding wheels work?
Grit cemented together.

The grit can scratch all sorts of things, but the binder is the weak point.

People don't talk much about getting scratches on quartz or granite. They worry about marble and soapstone.

blondelle thank you for doing the hard work of "doing the math" (i.e. doing the real work without talking about it in theory), and then posting your observations. Just for the heck of it I might just go take the sharp corner of some quartz samples and not trying all that hard see if I can put some pretty good scratches into other stone samples I have lying around -- but all I have is soft stone, not granite. I know I already tried the other test, scratching quartz with quartz. I confirm it the same result you got. Quartz just doesn't scratch much if at all, regardless of hearing that the binder is the weak part. I guess it didn't get that memo, or it just doesn't care for the theorizing. With a diamond blade I can cut it (and I did), but that is no surprise. I can't figure out what the "grit" and the binder has to do with this discussion. We all know that already. But, the epoxy as binder here sure has made the whole thing hard, and harder than any talking about the binder being the soft tissue would have us believe. So, thank you blondelle.

Guys -

As a point of order - the binder in most (if not ALL) Quartz products are
Polyesters - not epoxies. Unless most of the quartz manufacturers that all
run their products on a Breton line have changed their chem formulas to
epoxy (which would generally raise the price of the material to the consumer)
the binder - which is way softer than the quartz crystals has a lot to do with
quartz's ability to withstand scratching.

Don't get me wrong here - I am not trying to rile anybody up or start an argument
on Quartz vs Natural Stone or anything else....

Quartz products are really cool. They have a place in our industry, just like
Laminates, Concrete, Solid Surface, Stainless Steel, Glass Composites, and yes -
Natural Stone.

Blondell - after reading your latest post - you make sense and I see where
you were coming from when you made your statement about quartz and hardness vs granite

Thanks for clarifying what you meant

kevin