The 1 Month AA Medallion is commonly given by groups of Alcoholics Anonymous to members who have reached 30 days of continuous sobriety. While there is nothing official in AA about using medallions or "chips" a common culture has been created around giving medallions and the 1 Month medallion is usually the first coin given for a milestone reflecting some time of sobriety. There is a desire ship or 24 hours chip often given but the first coin given to reflect a time milestone is the 1 Month Medallion. Here is a picture of a common coin given, its bronze and made by Wendells Inc in Ramsey Minnesota. However there are aluminum and plastic and even wooden 30 day coins as there is no standard.
Each group is free to give whatever coin they want for 1 Month or give no coin at all. It's entirely up go the group conscience what they choose to do to recognize 1 month of sobriety.
The coin will usually say To Thine Own Self Be True around the rim of the coin. It will usually have the Serenity Prayer on back and will usually have the Three Legacies Triangle with 1 Month in the center. Around the triangle it will say Unity Service Recovery which are the Three Legacies of Alcoholics Anonymous.