The Magen David Adom (Meaning "Red Shield of David" or "Red Star of David" uses this emblem:
The emblem is not recognized by the Geneva Convention.
But the ICRC was aware of the problems that the Cross and Crescent could be seen as religious symbols. Iran used the Lion with Sun from their national flag (in red) as symbol for their relief agency from 1924 until 1980. This symbol is recognized by the GC.
The so-called "Third Protocol Emblem" is a red crystal:

National relief agencies can use their own symbol inside the "crystal" when working abroad:
Here is a link to several examples from Wiki:
Red Crystal Flags
Just tell me, when to shut up
See ya,
vonSteuben
The emblem is not recognized by the Geneva Convention.
But the ICRC was aware of the problems that the Cross and Crescent could be seen as religious symbols. Iran used the Lion with Sun from their national flag (in red) as symbol for their relief agency from 1924 until 1980. This symbol is recognized by the GC.
The so-called "Third Protocol Emblem" is a red crystal:

National relief agencies can use their own symbol inside the "crystal" when working abroad:
Here is a link to several examples from Wiki:
Red Crystal Flags
Just tell me, when to shut up
See ya,
vonSteuben