I recently bought 2 set of very fine quality stones labeled as
"vesonite" or "vessonite" garnets. Totally transparent - none over
about 0.75ct. Good crisp facets - almost no noticeable
If by "transparent" you mean colorless, chances are you have another
member of the grossular family (hessonite grossulars are
browinsh-orange to peach in color generally). The green grossulars
like Tsavorite and Merelani Mint grade into a near-colorless type,
usually with a very faint greenish tint. Several garnet species end
members would be colorless if pure, but in nature grossular is about
the only one to produce near-colorless stones. Grossulars also occur
in yellow and golden colors.
While refractive index often is not helpful with garnets, colorless
grossular can have a readable R.I. in the 1.731-1.736 range (Bank).
R.I. seems to decrease with purity (higher vanadium content results
in stronger green tints and higher R.I.) You might use your
spectroscope to check for vanadium or chromium. The name "vessonite"
is not indexed in either Rouse's "Garnets" or Shipley's "Dictionary
of Gems & Gemology" which often lists archaic or obscure names.
Of course if by "transparent" you mean something else, none of the
above applies, LOL. I hope you survived Charley unscathed and can
eventually find your refractometer!