The main device (symbol) in the Rockwood blazon is the chessrook. The two main tinctures (colors) are sable and argent.
Sable, the deep black so often found in Heraldry is believed to named from an animal of the marten family know in the middle ages as a Sabellinœ and noted for its very black fur 1A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Sable. In engravings, when colors cannot be shown it is represented as closely spaced horizontal and vertical lines, and appropriately is thus the darkest form of hatching, as this method is known 2Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 26. Although it may seem a sombre tone, and does indeed sometimes denote grief, it is more commonly said to represent Constancy 3The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P35.
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) 4Understanding Signs & Symbols – Heraldry, S. Oliver & G. Croton, Quantum, London, 2013, P53. In a sketch or drawing it is represented by plain, unmarked paper 5A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1847, P11.
Although we expect to find fierce creatures and fearsome weapons depicted in a coat of arms this is not always the case – sometimes simple household objects are used 6A Complete Guide to Heraldry, A.C. Fox-Davies, Bonanza (re-print of 1909 Edition), New York, 1978, P281. The Chess Rook is a typical example of this and has been used in heraldry almost from the beginning. The word “rook” comes not from the bird but from the Italian word rocca, a “castle” or “tower”. 7A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Chess-rook