So it's the glue. In electronics some old glues that were used during production decades ago turned corrosive over time, reacting to the air. This could be something similar. After 50 years the glue has gone bad and has begun to damage the thin obsidian/onyx layer.
Love this video, what an eye opener. Looking at the upside, they are beautiful in the eyes of the fans but the opposite is that vintage Rolex collecting is quite the minefield.
From a gemological perspective, I suspect a particular chemical reaction is at play here. Most "onyx" on the market is not naturally black but a chalcedony (white to brown) which was soaked in sugar and heated. The heat causes the sugar inside the stone to carbonize, creating a deep black color. There is no reason to expect the carbon to stay chemically inert over time. On one example in the video, there is a green spot peaking through, which looks strongly like oxidized copper from the brass plate behind the dial. In my opinion, you are looking at "onyx" (carbonized chalcedony) returning to its natural light-colored state as the black carbon reacts with other chemicals in its environment. I would be somewhat concerned that the carbon is reacting with components in the movement, which would compromise the movement's integrity. I'm going to send this problem over to an archeogemologist colleague of mine for his opinion.
You’re videos are very informative. I enjoy watching and learning more about watches through your videos.
😁🤝
Video esaustivo, grazie per l'ottimo lavoro
Thanks for your kind feedback 💯🙏🍻
So it's the glue. In electronics some old glues that were used during production decades ago turned corrosive over time, reacting to the air. This could be something similar. After 50 years the glue has gone bad and has begun to damage the thin obsidian/onyx layer.
Exactly 🤝💫
Very interesting ...
Thanks!
Love this video, what an eye opener. Looking at the upside, they are beautiful in the eyes of the fans but the opposite is that vintage Rolex collecting is quite the minefield.
It really is!
I wear an onyx ring, now I just need one of those Rolex...
Probably out of my budget though 😓
They look amazing though cheer's Felix
Yeah those onyx datejust are incredible pricey… what’s about an onyx Piaget? 😁🤝
How much
From a gemological perspective, I suspect a particular chemical reaction is at play here. Most "onyx" on the market is not naturally black but a chalcedony (white to brown) which was soaked in sugar and heated. The heat causes the sugar inside the stone to carbonize, creating a deep black color. There is no reason to expect the carbon to stay chemically inert over time. On one example in the video, there is a green spot peaking through, which looks strongly like oxidized copper from the brass plate behind the dial. In my opinion, you are looking at "onyx" (carbonized chalcedony) returning to its natural light-colored state as the black carbon reacts with other chemicals in its environment. I would be somewhat concerned that the carbon is reacting with components in the movement, which would compromise the movement's integrity.
I'm going to send this problem over to an archeogemologist colleague of mine for his opinion.
Yes, this is exactly the chemical reaction we are assuming :)
How about the Cellini 5071 obsidian? Is that genuine obsidian or something else?
It’s real obsidian :-)
RSC will ask u to replace d dial & tell u your dial has spoiled..like mine1 lol
Yeah haha