The Smithsonian displays a 168-carat Mackay emerald necklace
Documented collection fact: The Smithsonian lists the Mackay emerald and diamond necklace, with a 168-carat emerald, among the highlights of its permanent Hall of Geology, Gems, and Minerals.
EXIMUTC Market View
A documented museum specimen has a recorded identity and setting. Its 168-carat weight does not establish the quality or value of a different emerald; EXIMUTC evaluates each stone's color, clarity, treatment and report separately.
Source
Smithsonian National Museum of Natural History: https://naturalhistory.si.edu/exhibits/janet-annenberg-hooker-hall-geology-gems-and-minerals