Final answer:
The color Ultima and Antonio's mother wore to mass is not mentioned in the given information.
Step-by-step explanation:
In the given information, there are references to altars that are decorated with various colors. There is no specific mention of the color that Ultima and Antonio's mother wore to mass. The information provided includes details about the color white being associated with symbolism, such as it being the color of bone and breast milk. However, it does not mention the specific attire of Ultima and Antonio's mother. Therefore, we cannot determine the color she wore to mass based on the given information.