this is the reply I received from Citadel Coins..
We did a series of counterstamps in 2017 commemorate Canada's 150th anniversary. Some were done on 1967 dollar coins, some on 50 cent pieces, as these were the last silver coins that Canada struck for circulation.
The snowflake was chosen to represent Canadian winter. We struck less than 100 of these pieces, they were sold for $50.
We did a series of counterstamps in 2017 commemorate Canada's 150th anniversary. Some were done on 1967 dollar coins, some on 50 cent pieces, as these were the last silver coins that Canada struck for circulation.
The snowflake was chosen to represent Canadian winter. We struck less than 100 of these pieces, they were sold for $50.























