I also tested this piece with acid to confirm, as these brooches are typically not stamped. The pin is either sterling silver or steel.
A chip in the enamel under the letter Y. It is not noticeable until you inspect the piece. At one time there had been a piece to either clip on to something or to wear this as a pendant which has broken off. You may consider having a jeweler who works on antiques file it off or restore it.
Some wear to the jet glass. Brooch measures 1 across and 3/4 tall. Weighs approx 6.5 grams. The item "Georgian 14k Gold Enamel Mourning Brooch Pin With Name & Date 1829 Antique" is in sale since Wednesday, January 9, 2019.This item is in the category "Jewelry & Watches\Vintage & Antique Jewelry\Fine\Georgian, Pre-1837". The seller is "shophelloviolet" and is located in Austin, Texas. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Norway, Saudi arabia, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Viet nam, Uruguay, Switzerland, Russian federation.