You dish mat is retaining water against the stone, bleaching out the color.

Don't know but I think 2 years is WAY TOO long without additional sealing.

I think your "whole" counter darkened from more frequent cleaning, and the dish mat area, was never as light as what is now there, and it HAS leached color out, with wetness a constant factor.

Meaning I think Joe is right on the spot under the mat, and you are wrong as to how light it was originally : )

Excerpts below, link on the very bottom

"When granite — or other stones — are not polished, the surface always looks sort of gray, said Joseph Gargiulo, who heads Washington-area operations for Stuart Dean (800-322-3180; stuartdean.com), which does stone restoration work throughout the United States. “It’s like if you cut a diamond in half, it wouldn’t be shiny, it would be a gray color,” he said. “Same with granite. You don’t get the true color until you polish it. But with a leather finish, they don’t polish. So to get the color, they put on a color enhancer — a stain.”

Buy stone color enhancer, which is sold along with masonry supplies in home centers and building-materials dealers. (A 16-ounce jug of Miracle Sealants 511 Seal and Enhance is $29.97 at Home Depot.) Color enhancers are basically wetting agents that also seal. They aren’t tinted. Instead, they bring out the stone color in the same way that wetting a rock does, except that the darker, more vibrant color stays even after the stone dries.

Gargiulo said you should first wipe down the countertop with acetone or denatured alcohol to ensure the surface is very clean. These solvents are flammable, so extinguish flames first, protect your skin by wearing chemical-resistant gloves and provide plenty of ventilation. (Many color enhancers are solvent-based, so you’ll need good ventilation when applying that, too.)

After cleaning the countertop, apply the color enhancer to just the light areas, Gargiulo said, and then follow that with an application over the entire countertop. Check instructions on the product for how long you should wait between the coats. With 511 Seal and Enhance, Rustoleum, the manufacturer, says to wet the surface, wait three to five minutes, then wipe off the excess with a clean cloth. Wait one to three hours to apply a second coat."

https://www.washingtonpost.com/lifestyle/home/be-wary-of-a-leather-finish-on-granite/2019/08/09/864d3bd0-b4a3-11e9-8949-5f36ff92706e_story.html

I would just leave it alone. Natural stone is just that--natural, and it does what it's going to do. Same with marble. Trying to change it is just a waste of time. Appreciate it for what it is and spend your time in more enjoyable pursuits.

We use a drying mat on our granite counter. We put a hook up on the wall, and hang up the mat after use. You could put the hook under the sink cabinet.

You could dry the dishes, put it away, or just use the dang dishwasher. A mat or a towel is a 15 minute item, not 24/7. I detest the 24/7 thing....really hate it lol.

Quick question relating to this issue - I recently had leathered steel grey installed (I believe it's aka. silver pearl) and was told there was no need to seal it as this material just doesn't take in water, but the info above suggests that may be wrong? Or it is dependent on which type of black granite? I'm also using Method Daily Granite.

Thanks everyone. Having the drying rack there for miscellaneous non-dishwasher stuff is just a lazy habit that I need to work on. I'll find a place under the sink to store the rack and mat and see if leaving the area open to the air makes a difference. Glad to know I'm not crazy. Also thanks Jan for the detail on the color enhancer option, which I can always try in the future if it's driving me crazy.

"...and was told there was no need to seal it as this material just doesn't take in water, but the info above suggests that may be wrong? Or it is dependent on which type of black granite?"

There is too much variability in the porosity of stone to make blanket rules. Stone is not as"bulletproof" as some in the industry like to sell. Test yours and go from there please.

Ok thanks Joseph