Yes, there are several natural alternatives to harsh chemicals that you can use to clean your quartz countertop effectively while still being gentle on the surface. Here are some options: 

1. Baking Soda and Water: Create a paste by mixing baking soda with water. Apply the paste to the countertop, let it sit for a few minutes, and then scrub gently with a soft cloth or sponge. Baking soda is a mild abrasive that can help remove stains without scratching the surface. 

2. White Vinegar: Although vinegar is acidic, it's a natural and effective cleaner for many surfaces, including quartz. Mix equal parts of white vinegar and water in a spray bottle, spray the solution onto the countertop, and wipe it down with a soft cloth. Vinegar can help remove minor stains and disinfect the surface. 

3. Lemon Juice: Lemon juice is a natural acidic cleaner that can help remove water spots and mineral deposits. Mix the juice of one lemon with a cup of water, apply the solution to the countertop, and let it sit for a few minutes before wiping it clean with a soft cloth. 

4. Hydrogen Peroxide: Hydrogen peroxide is a natural disinfectant that can be used to clean quartz surfaces. Mix one part hydrogen peroxide with four parts water in a spray bottle, spray the solution onto the countertop, and wipe it down with a soft cloth. 

5. Soapy Water: A simple solution of mild dish soap and warm water can be used to clean your quartz countertop. Mix a few drops of mild dish soap with warm water, apply the solution to a soft cloth or sponge, and gently clean the surface. 

6. Vodka: Vodka is a natural disinfectant and can be used to clean quartz surfaces. Mix equal parts of vodka and water in a spray bottle, spray the solution onto the countertop, and wipe it down with a soft cloth. 

7. Borax and Water: Borax is a natural cleaner that can be used to create a cleaning solution. Mix one cup of borax with two gallons of warm water, apply the solution to a soft cloth or sponge, and gently clean the surface. 

Remember to always test any cleaning solution on a small, inconspicuous area of your quartz countertop before applying it to a larger area to ensure it doesn't cause any damage or discoloration. Additionally, it's essential to rinse the countertop thoroughly with water after cleaning and dry it with a soft cloth to prevent water spots or mineral deposits.