Acid etching is an artistic technique to imprint a design onto a surface. Acid etching is often used on glass, metal and stone. The acid erodes the surface, creating a different color and texture where it comes in contact with the rock. It is dangerous to work with strong acids, so take precautions when performing acid etching.
Things You'll Need
Rock or stone
Natural bristle brush
Create the design you would like etched into the stone by drawing it onto contact paper using a pen or pencil. Remove the excess paper from the design with a craft knife. The design shown in the contact paper will retain the current color of the rock, while the rest of the rock will be rougher and duller looking.
Remove the back of the contact paper to expose the adhesive and place it onto the rock.
Wear goggles and rubber gloves to protect your eyes and skin from the acid, and work outside in an area with good ventilation to allow the fumes from the acid to escape.
Pour hydrochloric acid evenly over the surface of the rock. Hydrochloric acid can be purchased from home improvement stores. Solutions that have been diluted will need to sit on the stone longer than an undiluted acid. Use a natural bristle brush to sweep acid over delicate areas to ensure even distribution.
Check the level of etching by washing away a portion of the acid with clean water. If the etching is acceptable, wash the entire surface with water.
Allow the rock to dry fully before removing the contact paper.
Hydrochloric acid is a strong acid. Protect your skin and eyes when using it and allow for ventilation so that you do not breath in the fumes. If you are working outside, acid poured into the ground can change the pH of the soil. Sprinkle baking soda over spilled acid to neutralize it.