U+085B Mandaic Gemination Mark

The Wikipedia has the following information about this codepoint:

The Mandaic alphabet is a writing system primarily used to write the Mandaic language. It is thought to have evolved between the second and seventh century CE from either a cursive form of Aramaic (as did Syriac) or from Inscriptional Parthian. The exact roots of the script are difficult to determine. It was developed by members of the Mandaean faith of Lower Mesopotamia to write the Mandaic language for liturgical purposes. Classical Mandaic and its descendant Neo-Mandaic are still in limited use. The script has changed very little over centuries of use.

The Mandaic name for the script is Abagada or Abaga, after the first letters of the alphabet. Rather than the traditional Semitic letter names (aleph, beth, gimel), they are known as a, ba, ga and so on.

It is written from right to left in horizontal lines. It is a cursive script, but not all letters connect within a word. Spaces separate individual words.

During the past few decades, Majid Fandi Al-Mubaraki, a Mandaean living in Australia, has digitized many Mandaean texts using typeset Mandaic script.