Asbestos in a late 1890s fireplace?

There are about 3000 different types of product around that were made from asbestos - but they are generally post first world war - and given the date of your fireplace you are probably looking at something like cast stone or marble (which can be granular) depending on its location. These were often finished to look a bit grander than white marble so I would not worry - seal it over and touch it up.