Final answer:
In Salesforce, the 'Error Message' field from a validation rule is available for translation in the Translation Workbench, which helps in displaying feedback in the user's preferred language.
Step-by-step explanation:
The field available as part of the translation workbench for a validation rule in Salesforce is the Error Message. When you create a validation rule, Salesforce allows the specification of an error message that will be displayed to the user when the rule criteria are violated. This message can be translated into multiple languages using the Translation Workbench to ensure users receive feedback in their preferred language. While descriptions and rule criteria provide necessary context and define the conditions under which the rule triggers, they are not translatable through the Translation Workbench. The formula itself, which defines the logic of the validation rule, is also not directly translatable as it consists of fields and expressions.