Gemini is a licensed crypto exchange, founded by Winklevoss twins, who are known for suing Mark Zuckerberg and winning $65million for claiming he has stolen their idea. As an exchange, Gemini operates only with 3 trading pairs: BTC / USD, ETH / USD and ETH / BTC. It decided to take a “vital few than trivial many” approach, focusing its services only on the best cryptocurrencies. Consequently, if a new coin appears on Gemini, it is a sign that it's worth your consideration. As regards specific features, we should like to mention availability of “Cold Storage” system, which guards the biggest part of coins from theft, keeping them offline. The reviews of this exchange are not 100% positive, so be careful and read additional information about it.