> I've read that "porcelain" contains  aluminum,
> another biological poison. And also a brain
> poison. Does anyone know if this is true?

Yes, it certainly does contain aluminum. The two most basic components
of most if not all ceramics are silica and alumina, along with various
other metals and minerals. However, it is bound up tightly in a
crystalline and glassy matrix. I don't think it can dissolve or leach
out at all, which is why pot sherds tend to remain unchanged for
millenia, and which is why porcelain and glass are used to contain
chemicals in laboratories. I wouldn't worry about it.