Arinola's "A Heart of Stone" is about a person who has been hurt so badly that they feel emotionally numb. The speaker begins by remembering a time when their heartbeat was gentle, "soft and moist," the sound of a living, human heart. But that heart brought "great and sad" pain, and so something changed.
Now the speaker hears only "screeching," a harsh, grating noise in place of the old soft rhythm. The heart has become "hard and dry," and the comparison to granite grinding on ice makes it sound cold and painful, not peaceful. The final lines push the idea further: ice seems to run through the speaker's veins, so the coldness isn't confined to the heart but spreads through the whole body.
The mood is bleak and chilled. There is grief here, but also a sense of loss, as though becoming hard was a way to survive pain that has cost the speaker their warmth.