Valentine's Day means chocolates, cards, candlelit dinners and, of course, valentines.

U.K. engineers designed the world's smallest valentine just in time for your loved one - an arrangement of gold and palladium atoms that is too small to be seen by a typical microscope.

The heart measures 5 nanometers (nm) by 3.5 nanometers - an incredibly miniscule size that dwarfs the engineers' efforts of an 8 nm heart in 2010. A billion nanometers make up a meter and an estimated 5,800 hearts would fit on a cross-section of a human hair.

Engineers who completed the work included student Alina Bruma and supervisor Ziyou Li at the Nanoscale Physics Research Laboratory, at the University of Birmingham, headed by Prof. Richard Palmer.

Li said he took images of the heart with an electron microscope that sees objects as reflections off electrons rather than photons.

The manipulation of gold and palladium atoms into a valentine isn't just an engineering gimmick, according to the scientists.

 The ability to control the structure of nanoalloys (gold and palladium) may one day lead to new materials with novel properties, having potential applications in areas such as catalysis and optical devices, Li told PhysOrg.