Minimal interference with historical material and maximum preservation is one of the basic principles of the scientific restoration and conservation of monuments of historical and cultural heritage. The creation of nanoscale and microscale inorganic coatings is a promising way to protect limestone and marble cultural heritage objects. We conducted a laboratory testing of a method for stimulating biogenic mineral formation on the surface of limestone-masonry samples from the medieval cave town on the Eski-Kermen plateau (Crimea, Russia). The results showed the formation of a layer of crystallites of 0.4 to 1.3 µm on the surface of the limestone, an increase in the average strength values of the samples by 28% from 12.3 ± 2.8 to 15.8 ± 2.6 MPa, a 42% increase in the specific surface area of limestone, an 86% increase in salt attack resistance, and preservation of the capillary water-absorption level. The obtained results show the potential of using biogenic mineral formation for the conservation and restoration of limestone.