Hard water can create a calcium buildup which is also called limescale or lime deposits.
White rings around faucet on granite.
You need a water softening system.
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.
There was a thread here a few weeks months ago about a similar sounding situation.
Maybe they used plummer s putty at your faucet connections.
Dampen a nonabrasive scrubbing pad with water and apply 2 or 3 drops of mild dish detergent.
The ugly white or yellowish rings around the faucet base aren t unusual.
Scrub the granite sink with the scrubbing pad.
When hard water sits on a granite surface and dries it leaves a visible mineral deposit that often creates white rings especially around faucets.
And your hard water may be contributing as well.
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.
Rinse the granite sink thoroughly with hot water.
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.
Hard water stains around the faucet.
It was deemed not a good idea as a plummer s putty ingredient tends to bleed through granite and leave the type rings you describe.
These are formed by the water that flows into the home and is fairly common in most cities.
It had to do with using plummer s putty to seal faucets at stone level.
A water filter may not be sufficient to deal with hard water.