Yes, you can seal a Marrone Breccia Marble countertop yourself. Sealing your countertop helps to protect it from stains, etching, and daily wear and tear. Here are the steps to seal your countertop yourself:

1. Clean the countertop: Start by thoroughly cleaning the countertop with a mild soap or stone cleaner and warm water. Remove any dirt, grime, or stains. Make sure the countertop is completely dry before proceeding.

2. Choose the right sealer: Select a sealer that is specifically formulated for use on marble surfaces. Read the instructions on the sealer label to ensure it is suitable for sealing marble countertops.

3. Test the sealer: Before applying the sealer to the entire countertop, its important to do a small test in an inconspicuous area to make sure the sealer does not discolor or damage the marble. Apply a small amount of sealer on a small section of the countertop and let it sit for the recommended time. Then, wipe it off and check for any adverse reactions.

4. Apply the sealer: Once the test is successful, you can proceed to seal the entire countertop. Pour a small amount of sealer onto a clean cloth or sponge and apply it evenly on the surface of the marble. Make sure to cover the entire countertop and pay extra attention to any porous areas or natural cracks.

5. Let it penetrate: Allow the sealer to penetrate the marble for the recommended time specified on the sealers instructions. This can range from a few minutes to several hours, depending on the product. Avoid using the countertop during this waiting period.

6. Remove excess sealer: After the recommended time, wipe off any excess sealer with a clean and dry cloth. Make sure you remove all the sealer residues to prevent streaks or a sticky feeling on the surface.

7. Let it cure: The sealer may take some time to fully cure, so its important to follow the instructions on the sealer packaging. Avoid placing any objects or using the countertop until the sealer has completely dried and cured.

Remember to periodically reseal your marble countertop, as the frequency will depend on the type of sealer used, the amount of use the countertop receives, and the recommendations given by the manufacturer.