Hard water stains around the faucet.
White rings around faucet on granite.
A water filter may not be sufficient to deal with hard water.
And your hard water may be contributing as well.
These are formed by the water that flows into the home and is fairly common in most cities.
You can also use a single edge razor blade to gently scrape away the residue or a safe on stone pad to scrub the area softly before rinsing and drying.
Maybe they used plummer s putty at your faucet connections.
The ugly white or yellowish rings around the faucet base aren t unusual.
For those tenacious water rings around a faucet resulting from hard water that sits on the surface try scrubbing softly with a brillo pad or gently scraping with a razor blade then wiping away the residue with a soft damp cloth.
For this kind of stain use a specially formulated granite cleaning product like granite gold daily cleaner and scrub with a soft bristled brush then rinse and dry with a soft cloth.
For really stubborn stains try using a poultice or extractor.
I get that they do not sit directly on the granite but soapy water certainly does get onto the granite particularly around the soap bottle and sponge.
Poultice products made especially for granite can be purchased at a hardware or stone surface specialty store or you can make your own paste using flour plus hydrogen peroxide.
Dampen a nonabrasive scrubbing pad with water and apply 2 or 3 drops of mild dish detergent.
Rinse the granite sink thoroughly with hot water.
Hard water can create a calcium buildup which is also called limescale or lime deposits.
It had to do with using plummer s putty to seal faucets at stone level.
There was a thread here a few weeks months ago about a similar sounding situation.
Scrub the granite sink with the scrubbing pad.