The Udachnaya pipe (Russian: Уда́чная, IPA: [ʊˈdat͡ɕnəɪ̯ə]; lit.

'Lucky') is a diamond deposit in the Daldyn-Alakit kimberlite field in Sakha Republic, Russia.

[3] Udachnaya was discovered on 15 June 1955, just two days after the discovery of the diamond pipe Mir by Soviet geologist Vladimir Shchukin and his team.

[4] The nearby settlement of Udachny is named for the deposit.

As of 2010[update], Udachnaya pipe is controlled by Russian diamond company Alrosa, which planned to halt open-pit mining in favor of underground mining in 2010.