| Original Message: Avventurina and Goldstone |
|---|
|
Hi Luann, I can't entirely agree with the Wiki exposition. I do agree (to my knowledge) that the quartzite mineral is named for the glass—and I agree that this is a really unusual occurrence (it usually being the opposite situation). You can look at avventurina glass and aventurine quartzite (as we know it from India), and see how they are different, or how they are alike. They have much in-common. As it happens, in the modern bead world we see a lot more green aventurine quartzite, and a lot of brown/golden avventurina glass. However, there is also a brown/golden (sometimes characterized as "red"—though it's not red) aventurine quartzite. And if this is what you were familiar with the comparison would be easier to make. The mica inclusions in quartzite are essentially white and non-metallic-looking, versus the coppery-red tone of the glass—but effect provided in both materials is reasonably similar. A BIG problem with the essay at Wiki is that it's filed under "Goldstone (Gemstone)"—which is very misleading. The monologue were better placed under "Avventurina Glass," with a mention of goldstone glass as a subsidiary. The author has a limited knowledge-base and understanding of the larger picture; and I would guess doesn't know much about glassworking. At Venice and elsewhere, the greatest proportion of beads that feature avventurina glass have been hot-worked (usually lampworked, but also enamelled). Sensibly, the class of glass is better named "Avventurina." It is ONLY when the glass has been lapidary-worked, like a mineral, that it is characterized as "goldstone." This distinction was respected by bead sellers (and some collectors) up until the 1980s, by which time apparently the distinction between them had become lost and/or was ignored or misunderstood (I say based on my observation). Another curious thing is that MANY people insist that there is a mineral called "goldstone," that the glass imitates. I have even been told this by Gemological Institute of America (GIA) graduates! This is totally inaccurate. There are TWO minerals that resemble goldstone/Avventurina—these being the quartzite already mentioned, and another mineral called "sunstone," that is a variety of feldspar. Sunstone reentered the marketplace a few years ago, after being reasonably unheard-of (in my experience)—it being the State Stone of Oregon, and that's where it's easiest to find specimens—until recently when commercial quantities were again available and now made into various products, including beads. sunstone is typically golden colored, with a metallic Sheen (in the better more-desirable specimens), and bares a decent resemblance to goldstone. However, many specimens are essentially clear and colorless, with very few inclusions, and hardly warrant being called "sunstone." Jamey All rights reserved by Bead Collector Network and its users |
|
|