This image is of a commercial bathroom countertop in a local restroom. It is not too difficult to see that someone made a poor choice for countertops particularly in a commercial high use setting.
Not only is this countertop unsightly, it is likely to be very unhealthy. It doesn’t appear that it has been sealed, or if it was sealed, it was a very inferior product.
We recommend sealing concrete countertops with either HMK S35 Matte Finish Sealer, or HMK S37 Satin Finish Sealer. Both of these products are professional grade Topical Acrylic Sealers. Once cured, they form a hard surface that deepens the color of the finished concrete. Another option is to use an Impregnating Sealer that is nearly invisible if you like the look of untreated (natural) concrete. Impregnators are not topicals, and do not leave a coating on the surface. We suggest using HMK S34 Impregnator for a natural look.
The picture below is an example of untreated and treated concrete:
The section on the right has been treated with a Matte Finish Sealer. The section on the left is raw and untreated. The small stripe in the middle is how an impregnator looks. On some colors the impregnators slightly darken the color, but do not leave a sheen.
Keep in mind that Topical Acrylics are a layer of acrylic on the surface, and when used in a kitchen, they can scratch if large pots slide across the surface, or knives are used without a cutting board. When impregnators are used, the protection lays below the surface protecting agains spills and stains, but you don’t need to worry about the topical surface being scratched. Note also however, that concrete is significantly softer than granite, and can scratch much easier no matter what treatment is used.
For more information on using Topical Sealers vs. Impregnating Sealers, please see the following LINK