Currency specified without type or quantity

If the currency is specified e.g. A person said >I bought from you (x Article) in exchange for silver (or gold or dinars or dirhams or rands or wheat), but neither type, nor quantity is specified, then such a sale is invalid. To specify quantity is an inherent condition of any sale. A sale will be valid if one says : > I have bought ( X article) in exchange for these (X amount) dirhams=, and he specifies the type, e.g. Misri (Egyptian) or Shaami (Syrian) dirhams and he specifies the quality, e.g. Perfectly minted or imperfect coins (Kitaabul Buyoo).