The two main devices (symbols) in the Mercury blazon are the cross flory and cinquefoil. The two main tinctures (colors) are azure and or.
The bright, strong blue color in Heraldry is known in English as azure, and similarly in other European languages – azul in Spanish, azurro in Italian and azur in French. The word has its roots in the Arabic word lazura, also the source of the name of the precious stone lapis lazuli 1A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Azure. Despite this, those heralds who liked to associate colours with jewels chose instead to describe blue as Sapphire. According to Wade, the use of this colour symbolises “Loyalty and Truth” 2The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P36.
Or is the heraldic metal Gold, often shown as a bold, bright yellow colour. It is said to show “Generosity and elevation of the mind” 3The Symbolisms of Heraldry, W. Cecil Wade, George Redway, London, 1898 P35. Later heralds, of a more poetic nature liked to refer to it as Topaz, after the gemstone, and, for obvious reasons associated it with the Sun 4Understanding Signs & Symbols – Heraldry, S. Oliver & G. Croton, Quantum, London, 2013, P53. In drawings without colour it is usually represented by many small dots, or by the letter ‘O’ 5A Complete Guide to Heraldry, A.C. Fox-Davies, Bonanza (re-print of 1909 Edition), New York, 1978, P76-77.
No other symbol appearing in heraldry is subject to as much variation as the cross 6Boutell’s Heraldry, J.P. Brooke-Little, Warne, (revised Edition) London 1970, P 47. Mediaeval Europe was a deeply religious and Christian and many of the nobility wanted to show their devotion by adopting the symbol of the cross as part of the arms. Since no two arms could be identical there arose many variants of the cross, typically involving patterning along the edges 7Understanding Signs & Symbols – Heraldry, S. Oliver & G. Croton, Quantum, London, 2013, P67, or fanciful, decorative endings to the arms of the cross 8A Complete Guide to Heraldry, A.C. Fox-Davies, Bonanza (re-print of 1909 Edition), New York, 1978, P128. The cross flory is typical of these, having each arm end in something very similar to the fleur-de-lys.
Natural objects abound in heraldry, and one category that gives especial delight are the many flowers and flowering plants that frequently occur 9A Complete Guide to Heraldry, A.C. Fox-Davies, Bonanza (re-print of 1909 Edition), New York, 1978, P262. The cinquefoil is also of this type, being drawn, at least a little, realistically and often to very pleasing effect. It is shown as five-petalled flower, each petal quite rounded but with a distinct tip. It is sometimes pierced with a hole in the centre and usually appears on its own, without any leaves. 10A Glossary of Terms used in British Heraldry, J.H. Parker, Oxford, 1894, Entry:Cinquefoil It has no fixed colour but can appear in any of the available heraldic tinctures.