I'm puzzled by the stats on this object. It has the blessed flag, which may have indicated it was a divinely powered item, but I see no reason for it to be so.
So I can either remove the bless flag and add magic, or leave it as-is.
Well it's invisible. I don't know of any priestly class that has the power to make things invisible. Only magic does that. Figure it has to be magic. Item was probably made long before those flags really were considered seriously?