Iglesia de Guayacán, Gothic metal church in Guayacán, Chile.

The Iglesia de Guayacán is a Gothic-style church with a metal frame and zinc-plated brass cladding, designed by Joseph Danly. It measures 21 m long and 10.2 m wide, with a central tower rising 27 m above the roof. Its 21 pointed-arch windows have coloured glass in cast-iron frames, and the interior is supported by five columns per side.

Before the church existed, Guayacán had only a small oratory serving the copper foundry of José Tomás Urmeneta, whose 35 furnaces made the sector the first mining centre of the Coquimbo Region. In 1887 Maximiano Errázuriz Valdivieso, principal partner of the Guayacán foundry, commissioned the design through his daughter Amalia Errázuriz Urmeneta in France; the Belgian firm Société Anonyme des Forges d'Alseau erected it in 1889. It was handed to the people of Guayacán in 1903 and declared a National Monument on 14 December 1977.

The church is dedicated to the Heart of Mary, as its alternate name Corazón de María indicates. Its 1889 inauguration was led by Monseñor Antonio Orrego, bishop of La Serena. From 1966 the Dutch priest Juan Van Hecke revived services and installed a new clock in the bell tower, and a carillon he built was inaugurated on 11 September 1970.

The church stands on a stone foundation of roughly cut blocks that levels the sloping ground, so the front differs in height from the rear. Its frontage measures 10.2 m wide by 21 m long, with a 27 m tower over the entrance and 21 pointed windows: 3 at the front, 8 per side and 2 at the back. The sacristy, 4.51 by 4.3 m, sits behind, giving 233.6 m² in total.

The church was shipped from Antwerp aboard the German steamer Biancas in early 1889 as nearly 400 packages of metal sheets. A Belgian engineer directed the assembly, which was finished on 2 March 1889, and the Bishop of La Serena, Antonio Orrego, inaugurated it.