Gemini is a legitimate and trustworthy US-based cryptocurrency exchange that was established in 2014 by the Winklevoss twins. It is a New York trust company , and is regulated by the New York State Department of Financial Services (NYSDFS). Buy with cryptocurrency: Gemini launched its Gemini Pay program, which lets you make retail purchases with cryptocurrency. There are over 30,000 participating retailers, and you can pay with bitcoin, gemini dollar (GUSD), ether, litecoin, zash, or bitcoin cash.