Rarity Ratings
 
When describing the rarity of Byzantine gold coins, most of the traditional rarity ratings do not apply.  The biggest reason for this is the rarity of Byzantine gold coin collectors.  Therefore, I have assembled and use the following rarity rating schedule while listing my collection.  It would be absurd to use this scale for US coins, but I feel that it applies well for Byzantine gold.
 

Unique	Only 1 known
Extremely Rare	2 to 5 known
Very Rare	5 to 10 known
Rare	10 to 20 known
Scarce to Rare	20 to 50 known
Scarce	50 to 250 known
Common	More than 250 known

 
 
Desirability Ratings
 
When describing the desirability of a particular Byzantine coin several factors must be considered and are therefore the opinion of this collector. The desirability of a particular coin, though, affects the value dramatically. Simple demand increases/decreases the desirability and therefore increases/decreases the relative cost.
 
 

Must Have	Reserved for representative common coins for an emperor, that are never expensively priced.
Extremely High	Coins that have special qualities, rarity or interest, i.e. Consular pieces and examples from short lived emperors.
High	Coins that are significantly rare or exhibit interest that a large proportion of collectors would be appreciate.
Medium	Coins that have moderate interest and would appeal to a significant number of collectors.
Low	Coins that would appeal only to a small number of collectors.
Extremely Low	Coins that only would appeal to a specialist or variety collector.