The stone--opal.
“Take the metals, for instance. The metal presented is copper, which is
fourth in the list. The question would be:
“‘Do you know the metal?’
“If steel, which is ninth in the list:
“‘Now, what is the metal?’
“Sex, countries, materials, fabrics, watches, are as follows:
OF WHAT.
[This set to describe the sex, etc., of the pictures.]