Wikipedia
Cifrão
The cifrão is a currency sign similar to the dollar sign ($) but always written with two vertical lines: . It is the official sign of the Cape Verdean escudo ( ISO 4217: CVE) and a common sign of the Brazilian real ( sign: R$; ISO: BRL).
It was formerly used by the Portuguese escudo (ISO: PTE) before its replacement by the euro and by the Portuguese Timor escudo (ISO: TPE) before its replacement by the Indonesian rupiah and the US dollar. In Portuguese and Cape Verdean usage, the cifrão is placed as a decimal point between the escudo and centavo values (e.g., 2$50). The name originates in the Arabic cifr.