You don’t see too many harp guitars in use. They’re somewhat rare.
A harp guitar can easily be described as basically a combination of the harp and the guitar, with several more strings than what you’re accustomed to seeing on a normal acoustic guitar. With a history dating back over two centuries, the harp guitar is unique. The American version is known for its hollow arms, double necks and/or harp-like frame, accommodating extra bass strings.
Back in the early 1900s, the Gibson Mandolin-Guitar Company in Kalamazoo, Michigan, made harp guitars. One model, from 1919 for example, is a sixteen course style instrument with a spruce top and birch back/sides. GIbson made four styles of harp guitars from about 1903 thru the 1920s.
What makes a guitar a harp guitar? It looks like a guitar, but can have several “floating” unstopped strings that can be used for individual plucking. Typically, there’s at least one unfretted string off the main fretboard, played as an open string.
There are acoustic versions of the harp guitar as well as electric ones.
Did you know Alaska Specialty Woods offers the best grade dyer harp guitar boards made from non-figured Sitka Spruce? These boards are cut from a tree that blew down prior to 1963. With a nice grain and some occasional bear claw starts, this wood helps make for a stunning harp guitar look.