We use South American mahogany for all our carved signs. Mahogany holds paint better than most woods and is nearly impervious to rot; timber that has a redish color (mahogany, California redwood, and red cedar) all possess a natural fungicide. We only use the best 23k German gold leaf; it's rich looking and extremely durable. The Gracie's sign has a "smalted" (crushed glass) background. Smalt is particularly good when the background is to be either in the red or blue family as those colors are prone to fade.
The "246" residential sign found here is 19"high x 16" tall and carved on both sides. The lettering and trim are finished in 23k gold leaf.