Topic: possible Rubine bowl.

[Paul S.]

thanks to all for your input - and at first I thought it seemed quite easy to define the various shades/depths of 'red' glass - and how to describe their make up.   Having looked through some of the books, I now find that I am out of my depth with this matter, so won't add anything of substance to Leni's comments.   It truly is a minefield of descriptions, and the only thing I would repeat is my earlier comment that the Sowerby 'sealing wax red' is almost certainly the result of combining selenium and cadmium sulphide - a red which is quite recognizable once seen - unlike the general ruby reds such as this Rudolfova Hut bowl (if indeed it is theirs).    Coming back to Leni's comments about gold chloride, and to illustrate the point that the 'red' colours can be mega complex  -  if the batch is not heated enough the gold particles remain too small, the glass is decribed as 'unstruck', resulting in a pale yellow tint to the glass.  If the material if overheated the particles expand to produce a blue tint i.e. 'overstruck'.  So unless you get it right, no red glass.      Frederick Carder knocked out something he called Selenium Ruby Glass, which contained cadmium selenide plus zinc sulphide, which sometimes shaded to orange - and so was then called 'Cadmium Ruby Glass'...............agghhhhhhhhh  I think you could write a whole book just on red glass and how to achieve it.
Anik - thanks for your comments - afraid I'm no wiser yet
P.S.   Sorry Emmi  -  just no way I could keep this one any shorter
 

[Lustrousstone]

I don't know if your tentative ID is correct, as the CD doesn't show the base of the bowls. but

As I have mentioned, I was puzzled by the fact that Marcus Newhall did not refer to 'ruby' in his book.

Marcus was only talking about Sklo Union colours, not about any colours that may have been produced before the Union was formed.

I might even consider looking at the USA for a possible origin

[Paul S.]

thank you Christine   I am presently at work so unable to re-check  -  but must admit that from memory I thought a base showing these concentric circles was illustrated (on the CD only, of course).
Your point about pre-Sklo Union I accept, thanks for making me aware of that information  -  and if Pamela's images are anything to go by, then ruby seems to have had limited appeal.   The only example shown is, I believe, from Brockwitz.   

[Paul S.]

Can confirm that page 11 does in fact carry an image of the design of the base - and this does have the circles which agree with this particular bowl.    So does seem quite probable, so far, to remain on track for Rudolfova Hut - unless as I commented earlier that the mould was hived off elsewhere at some point in its history.
Had meant to also say, re the discussion about 'red' glass, that two books which give give good information on the subject, and worth reading, are............
one................'The Illustrated Guide To Glass'  -  Felice Mehlman .....      a very good read anyway
two...............'The Encyclopedia of Glass'  -  Edited by Phoebe Phillips.......has a short but very good chapter on the technical issues of the chemistry of glass.
Paul S.