I apologise most sincerely for not having spotted the two entries earlier, Charles.
I am sure everyone will be interested in both of these posts so here are the links.
1. Information about the Londonderry emeralds.
For the entire discussion see https://mb.boardhost.com/historyroyaljewels/thread/1581053500.html
2. For information about the Londonderry rubies
For the entire thread see https://mb.boardhost.com/historyroyaljewels/thread/1624390790.html
I am sure that others will have questions, so I will leave mine for now.
Again a very warm welcome Charles! It is wonderful to have some expert knowledge about these very interesting jewels.