Dickinson uses various types of surfaces, such as wood and lead, to describe the narrator’s feeling after having such pain. The different consistencies like the lead, quartz, and wood might show the mixed feelings that the narrator is feeling and he/she is unsure of they feel or how they should feel. On the other hand, lead and wood have different densities. Lead has a density of about 11.34 g/cm^3, whereas wood (depending on which kind) has a lower density than that of lead. Maybe Dickinson meant that when the narrator was in his ‘lead’ state, he/she was feeling pretty low because when an object has a high density such as lead, the object tends to be heavier. Being heavy usually means you are down and sorrow in terms of emotion. When the narrator was in his/her ‘wood’ state, he/she was probably in a more joyful mood because wood has a lower density, and when wood for example is in water, it floats. So maybe the narrator was figuratively lifted from his/her low spirits after the great pain in his/her ‘wood’ state.
Also, I felt that Dickinson was contradicting herself when she said ‘The Nerves sit ceremonious, like Tombs”. Tombs are not seen as joyous, or is Dickinson looking at the tombs in a different way? Could it mean that the tombs are seen in a positive light because the people who suffered from great pain but died are now in a more peaceful place? They are no longer enduring pain, they are in tombs with nothing hurting them, and that, in a way, is ceremonious and victorious?