I know rubies are fairly dense, but I don't know what size to make
them. I am envisioning earrings approximatly one-half inch
long--is that too big for rubies? What I need to know is the size
of the rubies in carats and the value in dollars. I need this in
current terms--I know carats weren't standardized until much later
and I don't know French monetary units. The story is set in the
90's, in the United States.
Earrings of the time period that you indicate, were of Girandole
type. As a rule, they were very large and elaborate, especially made
for royalty. In those times, earring were made to match hairstyles,
which were very tall and complicated affairs. As a matter of fact,
most of the Girandoles of the period, were constructed with loops for
the silk band to support the earrings. Silk bands were woven into
hair to support earrings weight.
Earrings were always accompanied by at least a brooch and a bodice
ornaments, and very frequently they were part of elaborate parure.
Since were are talking about royalty, a political message was often
made a part of the design.
If was almost mandatory for jewelers working on royal commissions to
use a lot of diamonds. Ruby as a center stone is fine, but it should
not be too small. I would not worry too much about realism of the
size of rubies, because history is replete with confusion about red
stones. It is only in 20th century we learn reliably distinguish
between rubies, spinel, rubellite, and garnets. It is actually would
be an impossible task to make ruby earrings of stones more than 5
carats. It would take more than a lifetime to find 2 stones of that
size which would match enough, to be used in earrings.
As far as metal is concern, - it was silver backed up with gold, and
gold was often 14 kt.
Incidentally, my consulting fee is a signed copy of your book. Good
luck with your project.