This thread will do michellq
. I was reading elsewhere that silver tiara frames and fittings do tarnish and require regular cleaning. I recall one person saying that he was surprised with the Spencer Tiara when it was on exhibition in the US because the frame was tarnished. That would indicate it hadn't been coated or plated to protect the sheen. Gold doesn't tarnish so much but is heavy and expensive. Platinum is also expensive, but is very strong and therefore less of it is needed to hold everything together. Hope this helps.
Additionally, when the Spencer tiara was made (Georgian period), the technology to cut diamonds for maximum brilliance as we see they today didn't exist. That didn't happen till early 20th century.
So, to give the usually rose-cut or, later, old-mine cut diamonds more sparkle, they were generally set in silver around the stones themselves, with gold underneath to give greater strength, as an all-silver setting would be too soft and bendy. White gold could also be used, but generally on Huguenot-made or -designed Georgian pieces, the settings were silver above, yellow gold below.
I've not seen the Spencer tiara to say for sure, but it's obviously a costly and well-made piece, so I'd speculate that this is how it was constructed. So, yes, the silver around the diamonds would indeed tarnish and need careful cleaning so as not to remove the patina. Nothing looks worse than a stripped silver setting with old stones; you really need the antique patina to make it look its best.
I only happen to know because when I started collecting old pieces, I was taught a lot about them by the dealers. My Georgian and Victorian pieces are almost all constructed this way: silver to give sparkle to the stones (and make diamonds look whiter and cleaner), gold to strengthen the framework of the piece. Also it's rather cheaper than an all-gold setting, which may have been a consideration.
I seem to recall reading somewhere that a lot of the English Georgian jewelry designers/makers were refugee Huguenots from France, and pieces like the Spencer tiara were likely Huguenot-made. Please correct me, someone, if I'm mistaken.
