When it comes to finishing engraved slate coasters, several options can enhance their appearance while protecting the surface. Here are some recommended finishes:

• Sealer: A clear acrylic or polyurethane sealer is ideal for providing a protective layer over the engraved surface. This finish can help prevent moisture absorption and staining, ensuring the coasters maintain their beauty over time.
• Natural Oil: Food-safe mineral oil or teak oil can enhance the natural color of the slate while offering a level of protection against spills. This option is particularly popular for those who prefer a more natural look.
• Matte or Satin Finish: For a less glossy appearance, matte or satin finishes can be applied. These options reduce glare and highlight the engraving without overwhelming the natural texture of the slate.
• Color Stain: If a more vibrant look is desired, color stains can be applied to the slate. This allows for customization while still showcasing the engravings.
• Varnish: A water-based varnish can provide a durable finish that resists scratches and wear while maintaining a clear view of the engraving.

Choosing the right finish will depend on the aesthetic preference and practical use of the coasters.