Old Style
WWII-era pins. This style logo can be seen in Martin advertisements from (at the least) 1941 to 1947.

Five year banner-style pin.
Five year wreath-style pin.
Ten year wreath-style pin with blue stone.
Fifteen year banner-style pin with red stone.
Unknown year wreath-style pin (almost certainly a 15 year pin). Alternate wreath-style with stone at top of pin.

New Style
I believe these to be post WWII pins. It looks very much like the stone colors were retained from the previous style (eg, blue for 10 years).

Five year pin.
Five the reverse of the above five year pin showing an example of a "signed" pin.
Ten year pin with blue stone.
Fifteen year pin with red stone.
Twenty year pin with green stone.
Twenty five year pin with white stone.
Twenty five year pin variation. Note that the "Martin" sash is at a different angle and the white stone is larger.