Topic: Cobalt Bowl with swirly markings inside

[catshome]

I used this bowl as the example in a 2006 thread (link below for reference), which was discussing the different names for blue glass – Bristol, Cobalt, Irish – and trying to come up with a way of differentiating between them. 

https://www.glassmessages.com/index.php/topic,6818.msg58061.html#msg58061

The bowl itself was not really discussed and, as it has just appeared out of one of the boxes, I thought I’d see if anyone could help identify it.

Approx 10.75cm body diameter, 7cm rim diameter, 6cm high, 5.5cm base diameter, weighs 408g.  Foot rim 4mm wide (with some nice wear marks) around a slightly concave base, but no obvious polished pontil mark.

The glass is a lovely, deep, purple-blue.  The rim curves very slightly over/under.  Inside the bowl, the base has some distinctive swirls over a slightly matt finish.

The closest piece I have had (may still have in a box somewhere) was a cobalt thumbprint bowl by Elsa Peretti.

All ideas welcomed,
thank you. 
Cat

[catshome]

All about the base - three attempts....the middle one is probably closest to what the naked eye would see.  The other two appear to reveal a beautifully polished pontil mark, but I think it's just the light!

[chopin-liszt]

My family had a glorious little red bowl just like that - it had a Davidson's paper label on it.
Davidson's Crystal, I think, not glass.

[Paul S.]

so what are we saying cat  -  that the depression under the base is mould formed, rather than ground and polished  -  I thought it looked moulded, but could be wrong.
Those swirly marks remind me of how glass sickness sometimes affects the surface of glass  -  might this one have been acid treated do you think?