Post subject: Re: Vasyl007 Collection of Bubbles in Glass
Posted: Sat Aug 19, 2017 5:13 pm
Established Member
Joined: Thu Nov 17, 2016 11:11 am Posts: 43 Location: Northwest USA
Vasyl007,
With your interest in minerals/gemology being very strong, I would recommend that you invest in some simple gem tools to assist you in your studies. Also there are lots of online videos and lessons on gem identification that you will enjoy. I am old to rocks/minerals but new to gems and am going through the same journey as you.
In the past year I have learned that the big gem labs as well as local gemologists can return a different ID on gems than their counterparts have. I have also learned that there is a difference between an air bubble and a gas bubble. Air bubbles always point to glass while gas bubbles may be present in natural gems. I have learned that some gems like spinel often have round bubble-like inclusions but are in fact, natural gems.
I haven't seen a natural gem yet that has as many bubbles as your first example and such a cluster of bubbles is rarely found in antique glass used for commercial products. However, such bubble clusters are commonly seen in slag glass (scraped off the top of molten glass) as well as being common in glass that has been through a fire and re-melted. Camp fires are a good place to discover glass with bubble clusters.
Antique glass prior to the 18th century will have lots of bubbles but they are normally not in large clusters. Glass during and after 18th century will have fewer bubbles but they are still present. Most glass made after 1930 has far fewer bubbles due to the addition of lead in the glass.
Keep learning and discovering, this is a great hobby.
Post subject: Re: Vasyl007 Collection of Bubbles in Glass
Posted: Sat Aug 19, 2017 6:40 pm
Site Admin
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Quote:
In the past year I have learned that the big gem labs as well as local gemologists can return a different ID on gems than their counterparts have.
Therefore, may I presume that the "big labs" like GIA, AGL, AGS, Stone Group, Lotus, are correctly identifying unknowns and local gemologists (?) with limited instrumentation and experience make mistakes?
Quote:
Air bubbles always point to glass while gas bubbles may be present in natural gems. I have learned that some gems like spinel often have round bubble-like inclusions but are in fact, natural gems
I don't think I agree with this. Please post some examples.
As far as natural spinel, there can be inclusions which may look like bubbles but are actually included crystals. Example:
Bubbles can be found in phase inclusions in natural stones....is this is what you are referring to? They can also be found in fillers used to enhance natural stones....and of course naturally occurring in obsidian and amber.
Here's an old thread from 2006 discussing the same thing: viewtopic.php?t=999
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