Have your fabricator dig some stone slurry out of a pit or machine bed. If it's dry when you get it, just add water and rub it on the "scratch".

These guys who think they're signing away future problems make me laugh. You could have clients sign in the blood of their first born male child and if they don't like it, you're still the idiot for doing it and they're not paying.

I finished a wood sample for a woman years ago, cut the sample in half, had her sign my side and finished the built in. "It's too dark!" she cried (literally). My sample meant nothing and she stuck me for $700.00.

Thanks, Trebruchet, for answering my cry for help. I want to make sure I understand you correctly. Are you saying that you think it is a scratch? Or is your remedy the solution whether it's a scratch or merely metal flakes on the sample? If so, that's not a solution I can do or want to do on a regular basis so that might knock this stone out of consideration. It still boggles my mind, though, that the stone could be scratched. I thought the caution was not to cut on stone because it would dull knives, not that knives would scratch stone.

I don't know exactly what the waiver states since we didn't get that far. I had heard all the warnings about fingerprints, etc on honed surfaces but in all my 'net searches and pouring through GW, that complaint was almost solely concerning Absolute Black. I have never heard of nor read any concerns about scratches showing on honed surfaces.

Sorry for your bad customer experience.

Hi Lisa,

I don't see any cause for alarm quite yet. It sounds to me like the knife blade left a trail of material on the stone, which also sounds like it's hard to remove. But this doesn't mean there is anything wrong with the stone.

A better test is to do the glass scratch test, in which you scratch the stone against a piece of glass. You'll need a sharp edge to do it, and try a few different areas of the stone. That will tell you the relative hardness of the stone. All rocks in the 'granite' family will easily scratch glass.

If a stone becomes scratched it's because something that is harder than the minerals in the stone did the scratching. This basic physical fact doesn't change if the stone is polished or honed. That said, the surface finish can affect other materials leaving a trail on the stone. I'm guessing this is what they are warning you about. If the surface is rough and you slide a terra cotta bowl across the stone, you'll get a little trail of powdered terra cotta left on your stone. So, this may be something worth testing out on the honed samples.

As for the names of stones, I couldn't agree more. They are impossible to track and compare, and I suspect that's no accident. Hence the GW practice of getting samples and testing the heck out of them, just as you are doing. Nice job!

lisa_a:

Metal marks are common on stone. Stone slurry is just one shot at removing them.

The name game-easy to lose your mind.
There are only about 27 true granites all the rest sold as granites are considered mercantile granites by the industry.
They are stones that are geologically different from granite but similar in some regards.
You will need to test any samples you get as stones will display different characteristics.
It is also possible that when you scratched the arabian leathered sample it may have been color enhanced.
A color enhancer on the surface will bring out the depth of color making it appear blacker than the other samples under the same name. It may have been the color enhancer that scratched.
Don't drive yourself to crazy but find a great fabricator who knows stone and is passionate enough to pass on his knowledge.

Srosen- That is fascinating. Do you happen to have a list or resource I can read to see what is "true" granite? I am curious if mine qualifies.

Yours are not granite because there is no such thing as a black or dark-colored granite. The whole thing about calling any igneous rock granite used to drive me crazy, but I've softened. Whether your rock is granite, diorite, gabbro or quartzofeldspathic gneiss, it doesn't actually matter much from the kitchen point of view, they all perform very similarly but look totally different.

Here is a nice page that describes what granite is and even acknowledges that the stone industry uses the name differently than geologists do.

Here is a link that might be useful: all about granite

"You could have clients sign in the blood of their first born male child and if they don't like it, you're still the idiot for doing it and they're not paying. "

Add the words of death: "Well, you're the professional". which translates into "I know i didn't listen to you but now I'm not happy and you should have MADE me listen to you and its your fault and you better fix it because I am NOT happy!"

Can you tell I'm in the process of dealing with a particularly difficult customer?

re: the line; it is most likely a metal deposit that can be removed. This is why we tell people not to cut on "granite" even tho it won't hurt the stone because it will wreck their cutlery. On a polished surface the metal line can usually be removed easily with steel wool.

karin- Thanks for the info. I did a bit of research and according to a table I found, my granite is a porphrytic alkali granite and it dates back to the uppermost proterozoic to Cambrian period. So my countertop is roughly 540 million years old.

Here is a link that might be useful: table of granite and marble

Cool Texas Gem!

Which granite do you have? Amazing how old those rocks are, eh?

Thanks for the link. I had been using an older, messier version of this same table, but this one is much better. Bookmarked!

I have Giallo Napoleon, I just love it!

Thanks, Trebruchet, for clarifying your suggestion. Curious that the knife left metal marks on only the Arabian Black sample, not the Blue Pearl samples. I've looked at my Blue Pearl samples from all angles but there aren't any metal marks anywhere on them.

karin_mt, I was hoping you'd comment. I've learned so much from your 5 Countertop Geology threads (loved my 3 years of HS Earth Science classes; reading your threads made me realize how much I've forgotten). To clarify to you and everyone else, I'm using "granite" the way the industry does, not as a geologist would.

The only stone in consideration that I feel I need to check for hardness is Arabian Black. Blue Pearl is a known quantity. I'll have to wait until I head downtown again since my samples are granite tiles that I had resurfaced (no sharp edges).

I slid a Fiestaware plate across the tiles so the rub marks I see on the honed sample could be a trace of pottery dust. Funny how I'd see it only on the honed sample, which is the smoothest, and not on the leathered samples. I suppose the trails could be there but the slightly rough surface hides it better. I'll give the honed sample a good polish with a microfiber cloth and see what happens.

srosen, great suggestion, however I don't think a color enhancer was applied to the tiles. Even if it was, wouldn't it have been removed when the tiles were resurfaced? My leathered sample of Arabian Black looks exactly the same as the leathered slabs of Arabian Black and I know the slabs have not been enhanced. They told me that was something the fabricator would do if we wanted that treatment.

btw, the fabricator we hope to work with is one of the top fabricators in the area. I don't doubt their knowledge or skill (their seams are incredible!) but I am wondering if perhaps we're having a terminology disconnect. That can be remedied with another conversation.

oldryder, thanks for the tip. I'll try steel wool on my sample and see what happens. Much better to do test runs on my samples than on my counters after they are installed! Sorry that you're dealing with a difficult customer.

Texas_Gem, great links, thanks for sharing!

karin_mt, scratch what I wrote about having to wait to do the glass scratch test until I headed downtown again. The underside of the tiles are sharp enough to do that test. And - yay! - all 3 of them scratched the glass bottle without much pressure. So, that definitely points to the silver marks being metal from the knife blade and not scratches in the stone.

Nice! It's always nice when things work out in a way that makes sense, and that is the result I'd expect. So, now all you need to worry about is metal or ceramic leaving trails of residue on your stone, which sounds like a solvable problem.

Texas Gem, quite right. Giallo Napoleon is a textbook example of granite. Nice one!

Great thread-
Yes Lisa that's correct most color enhancing will take place after installation. But you never know with samples.
Use fine steel wool.
Bon ami makes this very fine abrasive cleaner.
Its a liquid-if you know of it. It may work great on those marks without abrading the stone.
Glad you have a great Fabricator-that seems to be the key.

Thanks, srosen, for the tip about using fine steel wool. I might have grabbed a Brillo pad from under my sink otherwise. :-) I'll look for the Bon Ami liquid, too. I suspect I won't need to use these remedies that often. My KD dragged the utility knife across the tiles with quite a bit of force to see if she could scratch them but since we've never done anything like that with our 20 year old laminate counters, it's unlikely we'll do that with our granite counters.

Thanks to everyone who has contributed to this thread. You've been a great help!