Joined: Fri May 12, 2006 11:24 am Posts: 7523 Location: Rome, Italy
You asked for the possibility of scanning inclusions inside gemstones, that is something it can be done only by using Confocal MicroRaman units, GemmoRaman is not a confocal unit so its not possible to scan inclusions. 2 examples of units used for that task are this one: http://www.thermoscientific.com/content ... scope.html which i use on daily bases and it costs around 90-100.000 $ depending on the configuration and this one: http://www.renishaw.com/en/invia-confoc ... cope--6260 which can cost even more than 230.000 $ if equipped with multiple laser setup. hope this will clarify the situation a bit.
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
Question. Treated chalcedony to make it black. (often referred to as black onyx) Is this treatment detectable with the Gemmoraman? In an article in G&G, 2003, Fall, there was a confusion about whether some black chalcedony was treated, or I should say a confusion as to HOW to prove it.
Quote:
To support this conclusion, we analyzed the material with the Raman spectrometer. The presence of two distinct peaks, one at 1600 cm−1 and the other centered at 461 cm−1, identified the black material as chalcedony and indicated the presence of a carbonized compound (sugar). In addition, infrared spectroscopy showed two peaks at approximately 2235 and 2133 cm−1, which our research has found indicate that the color is the result of treatment by sugar and acid (and/or heat). This material is typically known in the trade as black onyx.
Is this a conclusion you have confirmed with the GemmoRaman?
Joined: Wed Oct 22, 2008 5:00 am Posts: 344 Location: Finland
Quote:
Is this a conclusion you have confirmed with the GemmoRaman?
We have seen the 1600 cm-1 peak in treated black chalcedony, but whether it shows up in all the treated samples or not is unclear at this point. To clarify the editing of G&G- article: 461 cm-1 peak only indicates the sample is quartz. Chalcedony has an additional smaller peak or shoulder at 501 cm-1 (moganite) which the article does not mention. The 1600 cm-1- peak indicates the presence of carbonized sugar.
Users browsing this forum: No registered users and 14 guests
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot post attachments in this forum