Thanks for the picture, Karen!
You've identified the clock for me as a Tiffany & Co. piece, not a piece designed by Louis Comfort Tiffany. They didn't make the clock - they retailed it. They employed independent artisans to make their fine wares.
The Walter Durfee Westminster/Whittington chimes (I'm assuming this is a quarter chiming clock), the beautiful carving and the apparently excellent condition all contribute to the value of this lovely clock.
If it is in excellent cosmetic and working condition, its current retail (replacement or insurance) value is approximately $245,000. If you were to sell it, you could expect to get the fair market (private sale or auction) value of approximately 40% of the retail amount, or $98,000, depending on location and actual condition.
I hope this answer has been helpful to you, Karen.
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Thank you so much! Happy holidays!