Hard water stains in granite sink

Hello! Many of these comments are with good intentions but recommend products that are too acidic/alkaline based and can actually damage your sink. Here is what you need to do:

1. Do not use vinegar, Barkeepers friend, lemon juice, CLRS, or any other acidic or alkaline-based product. These are simply too abrasive for granite and can eat away at the top layer of your sink, called "etching." This typically appears as a stain but is much more difficult to deal with.
2. There are two possible solutions to this post's issue. The first is to deal with the possibility of mineral deposits or hard water spots. For mineral deposits and hard water spots, you need to use a product formulated specifically for granite sinks and hard water spots/mineral deposits. These products are hard to come across, and honestly, the only one I'm aware of is the Supreme Surface Composite Granite Sink Kit. Most other products are either too neutral to remove mineral deposits, or are too abrasive and damage the sink.
3. If the issue is not mineral deposits/hard water stains, then it is most likely due to "etching." Etching occurs from using abrasive products such as lemon, lime, CLRS, barkeepers friend, or vinegar on your sink. These require a more extensive and complicated solution. Mineral oil will not fix it; it will only hide it temporarily. For this, the solution is simply too extensive for me to write in one comment, so I recommend to reach out to your local installer/fabricator for advice, or honestly, I recommend just calling the Supreme Surface customer support for help, since they have provided me with the best & most honest advice in the past when I had this issue.

Good luck with solving your issue, and once again be careful: many recommendations on the internet about this issue are incorrect, and can actually damage your surface. It's often best to reach out to professionals in the industry, and not home-owners about granite and natural stone, since it's a complicated surface to deal with.