Topic: Balluster knop dram glass? help please.

[brucebanner]

Any thoughts on this one, very dirty glass with bubbles and brown streaks and a lot of base wear.

The closest glass i can find was described as a dram glass.

The ball stem is hollow.

4 1/4 inches in height, 2 inches across the rim and 2 1/4 inches across the base.

Regards Chris.

[bat20]

Hi Chris,do you think it's leaded?it looks like it may have a straw tone to the glass?

[brucebanner]

Not sure it looks straw coloured but glows light green under UV, im thinking it might be the oldest drinking glass i have found recently but i have had a good look through all my old glass books and can't see it.

It's either very old, very well used or very sandpapered.

[bat20]

Umm,not something I've come across before,has it got loads of small bubbles in it like say early soda glass?and does the wear look mossy or directional.

[bat20]

Probably way off as usual,but I'm thinking schnapps glass?

[Paul S.]

if the tone is yellowish, then it's not going to be lead.                      If you look in Barrington Haynes, he seems to be calling things like this  -  with a ball, or compressed ball - shape at the base of the stem - 'thistle stems' -   for obvious reasons.

I thought that might have implied such pieces were of Scottish origin, so I looked through Fleming's 'Scottish & Jacobite Glass' -  but no joy.
I did wonder if it might have been German.

I'd have thought it was a dram glass, but as for date I'm really not sure.

[Ivo]

looks like high manganese content which probably puts it somewhere 1870-1920, give or take a few.

[KevinH]

Not sure it looks straw coloured but glows light green under UV

"Lead glass" often (or perhaps usually) shows as light green under longwave UV - which is the type (range) of UV that most collectors use to examine items with. As Ivo says, the light green reaction is due to the manganese used as a decolourant.

A UV test for "lead based" glass normally requires shortwave UV. The reaction of "lead glass" under shortwave UV will normally be a clear and obvious shade of blue.

[brucebanner]

I'm using a bank note tester, not sure if that's longwave or shortwave, i posted a pressed glass creamer on here 1840'ish in date a couple of days ago and that glowed the same. The UV test on clear glass must have a date range as Ivo suggests? it could be a good indication of how old something is and if it's been copied or not.

If this little dram glass i have posted has a high level of manganese in it to be used as a decolourant why is it a dirty yellowish like colour?

[KevinH]

A standard bank note tester will be longwave uv.

Unfortunately, dating of glass by uv testing can only be very generalized. (And that applies to both longwave and shortwave uv.)

Manganese, as a decolourant, and therefore in a high enough percentage of the batch to give a green longwave uv reaction, was, I think, used from at least the "glass rediscovery" years of 15th century Venice. I am not sure when Manganese was generally superseded as a decolourant by such as selenium. But its use was certainly common up to at least the mid 20th century.

So on that basis, a green longwave uv reaction could indicate a date period of at least five centuries!

Some people have used the "brightness" of a green reaction to indicate a suggested time period, or even a particular factory / maker. Sadly, what some people see as a "bright green" reaction due to manganese is actually down to uranium - but some claims for "uranium glass" can often be an indication of "excess manganese".

Not an easy subject for me to understand or draw conclusions from - and that is just on the subject of manganese as a decolourant!