Flageolet

From MusiCAD

A flageolet is a style of playing on stringed instruments where a string is not fully shortened but only touched with a finger. A flageolet is usually displayed with a diamond-shaped note-head, either open or closed.

flageolet.jpg

Flageolets may be inserted using the trill menu and can be combined with other modifiers like fingering.

Diamond-shaped are also used for percussion notation to distinguish instruments.