The ability, technology, or in some circles, art of embossing stone has long since fallen through disuse to a loss of the ability to execute. Debossing, or carving, a stone surface has complete replaced embossing stone due to the level of difficulty and time needed to create effective products.
The Restful Exhibit Society originally favored stone embossing for its greater aesthetic in creating grave markers, signs and building adornments. However over the years its practice has fallen from those heights, is longer practiced even as a simple art form, and is not taught to apprentices as no masters of stone embossing remain.
Two notions contributed to the decline of the practice. First the time it takes to perfect a message embossed in stone is thirty times, or more, that needed to create the message using debossing or carving techniques. Second, embossed stone was susceptible to a high degree of wear over the centuries, eventually eroding these messages away into the smooth stone.
Note that embossing other media is still practiced, particularly with paper, where the effect is highly prized and carries a much lower expectation of longevity.