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Glass Identification - Post here for all ID requests => Glass => Topic started by: auliya on March 17, 2009, 07:41:06 AM

Title: Possible Murano Aventurine Bowl?
Post by: auliya on March 17, 2009, 07:41:06 AM

Good Afternoon,

This is my first post to your wonderfully informative board, so I hope I don't break any posting rules! I am in Australia and am having some trouble finding out anything about a deep red bowl I have. I think it may be Aventurine, and I was surprised last night to find that the back of it glowed green under UV light (I was checking another piece and it changed colour!). Does anyone have any idea who the maker might be, and if the back might be cased in uranium glass?

(http://i16.photobucket.com/albums/b48/auliya1952/th_DSCF1965.jpg) (http://i16.photobucket.com/albums/b48/auliya1952/DSCF1965.jpg)(http://i16.photobucket.com/albums/b48/auliya1952/th_DSCF1964.jpg) (http://i16.photobucket.com/albums/b48/auliya1952/DSCF1964.jpg)(http://i16.photobucket.com/albums/b48/auliya1952/th_DSCF1978.jpg) (http://i16.photobucket.com/albums/b48/auliya1952/DSCF1978.jpg)

Thank you in advance for any information
auliya

Title: Re: Possible Murano Aventurine Bowl?
Post by: Lustrousstone on March 17, 2009, 08:00:33 AM

Hi Welcome to the board. The gold looks like adventurine to me, but I don't think the glow is caused by uranium - it's just not bright enough. Also the outer glass looks to be clear, which means the glow is probably caused by manganese used as a decolorant. We also like to see the bottoms of bits of glass because the finish can often give clues to the origin and sometimes date.

Title: Re: Possible Murano Aventurine Bowl?
Post by: Ivo on March 17, 2009, 08:14:46 AM

Yes that is Murano, yes that is Aventurine and yes that is a nice bowl!

Title: Re: Possible Murano Aventurine Bowl?
Post by: auliya on March 17, 2009, 08:36:42 AM

Thank you for you quick responses :-)
Here are further 2 photos of the back of the bowl (I had to wait until it got dark enough here to photograph under the black light). I don't suppose anyone would know the likely maker?

(http://i16.photobucket.com/albums/b48/auliya1952/th_DSCF1982.jpg) (http://i16.photobucket.com/albums/b48/auliya1952/DSCF1982.jpg)
(http://i16.photobucket.com/albums/b48/auliya1952/th_DSCF1987.jpg) (http://i16.photobucket.com/albums/b48/auliya1952/DSCF1987.jpg)

Thanks again
auliya

Title: Re: Possible Murano Aventurine Bowl?
Post by: TxSilver on March 17, 2009, 10:59:00 PM

Your bowl looks like uranium glass to me. Several Italian makers used it on some of their pieces. The metal appears to be copper aventurine. It can be difficult to attribute these types of bowls. Usually they are just considered generic, meaning no one seems to know who made them. Murano-type bowls were also made in other Italian cities. I saw a bowl similar to yours the other day that had a Genuine Venetian Glass label on bottom, so I suspect your is made in Murano.

Title: Re: Possible Murano Aventurine Bowl?
Post by: Cathy B on March 18, 2009, 09:38:37 AM

I'd second that it looks it could be uranium. It doesn't look like any manganese glows that I've seen, and perhaps it's just your photograph?

Title: Re: Possible Murano Aventurine Bowl?
Post by: auliya on March 18, 2009, 12:13:32 PM

I confess I don't know exactly what a decolourant does, but the green is only on the back of the bowl, not the front where Aventurine is. It is quite a strong colour as well.

Thanks for your help with this, everyone
cheers
auliya

Title: Re: Possible Murano Aventurine Bowl?
Post by: Lustrousstone on March 18, 2009, 01:00:38 PM

A decolourant effectively removes the effects of impurities in the sand used to make the glass that give an undesirable colour tinge. The greenish Coke bottles you used to get didn't contain a decolourant. What colour is the glass on the back of the bowl in ordinary light?

Title: Re: Possible Murano Aventurine Bowl?
Post by: auliya on March 18, 2009, 01:32:10 PM

Well, it is red, as you can in the picture, I can't really tell if there is a casing of clear over it - but I don't think so. I also just discovered it doesn't need to be in a dark room to go green with the UV light, as you can see.

cheers
auliya

(http://i16.photobucket.com/albums/b48/auliya1952/th_DSCF1994.jpg)  (http://i16.photobucket.com/albums/b48/auliya1952/DSCF1994.jpg)(http://i16.photobucket.com/albums/b48/auliya1952/th_DSCF1995.jpg) (http://i16.photobucket.com/albums/b48/auliya1952/DSCF1995.jpg)

Title: Re: Possible Murano Aventurine Bowl?
Post by: Lustrousstone on March 18, 2009, 05:41:34 PM

It must be cased or at least have two different layers if it doesn't glow on the other side. You also never need to go in a dark room to see the uranium glow, although you might need to turn away from a bright light source. IMHO it just doesn't look right for uranium. I would expect something more like this colourwise

Title: Re: Possible Murano Aventurine Bowl?
Post by: johnphilip on March 18, 2009, 08:12:24 PM

Sometimes the casing is thin and difficult to see , the answer to this is to get a bowl fill it with water part submerge you glass at an angle look at the edge and you will see if its cased , use a plastic bowl in case the wet glass slips . regards .jp

Title: Re: Possible Murano Aventurine Bowl?
Post by: TxSilver on March 18, 2009, 09:06:52 PM

Another thought is that substances can be selectively applied to areas of the glass. For example, I had a 19th Century piece of Salviati glass that had strips of UV strongly-reactive glass in the foot. Why anyone added it, I don't know. You couldn't even tell it was there under normal lighting conditions. If the bowl was not cased, perhaps a thin layer of UV reactive glass was included before the bowl was blown, so it fused with the red glass of the bowl. Just a maybe.