The main device (symbol) in the Gaska blazon is the goose. The two main tinctures (colors) are azure and argent.
Azure is the heraldic colour blue, usually quite a deep, dark shade of the colour (there is a lighter blue that sometimes occurs, known as celestial azure). If colour printing is not available then it can be represented by closely spaced horizontal lines in a scheme known as “hatching” 1Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 26. The word is thought to originate from the Arabic lazura and it represents the colour of the eastern sky. It is also said to be the colour associated by the Catholic Church with the Virgin Mary and hence of particular significance 2The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P150.
Argent is the heraldic metal Silver and is usually shown as very pure white. It is also known more poetically as pearl, moon (or luna) 3Understanding Signs & Symbols – Heraldry, S. Oliver & G. Croton, Quantum, London, 2013, P53. In a sketch or drawing it is represented by plain, unmarked paper 4A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1847, P11.
We can consider the goose and duck together here as the former is quite rare, the latter appear in several forms, but both share the same meaning. Guillim, the 17th century author points out that such birds can swim, fly and run and thus their use may symbolise those who “have many ways of eluding their enemies”. 5A Display of Heraldry, J. Guillim, Blome, London, 1679, P158 Other names for the ducks especially mayh have been used because of some assocation with the family name, the smew may fall into this category. 6A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Goose and Duck