This beautiful Begonia is from Borneo, and thus far is unidentified. I’ve had it a little over a year and it has reached 8″ tall. The leaves are iridescent purple-black-blue with bright red abaxial (backside) leaf surfaces. The stem and (very short) petioles are the same bright red, and covered in small hairs. When you tilt the plant in low light, it looks rather reddish pink. Younger plants will show this coloration more readily, and tend to get darker as they grow, displaying more of a blue-black like the plant below.
Like many Begonias from this region, it is prone to melting. Despite this, it seems to be an easier species, not as finicky as darthvaderiana and usually the melting is confined to a single lower leaf.
The abaxial (back) of the leaves are just as beautiful,
The foliage strongly resembles B. opaca, however, the male flowers have a different number of tepals so it is unlikely to be a match.