Long before synthetic commercial fertilizers were available, farmers turned to bone meal to enrich soils in need of amendment. Bone meal is made from steamed and crushed animal bones, and is rich in phosphorous, a mineral that plants need for healthy root development and flower growth. It also contains calcium and a little bit of nitrogen, both of which are beneficial to plants.
Bone meal is taken up by plants slowly over time, so as long as it is used sparingly, there is little risk of 'burning' plants with too much of this fertilizer. There will be a slight chance as stated, the most important thing is to promote a maximum inspection + calculation.