Metamask
Metamask is a full fledged Ethereum wallet and dApp (Decentralized Application) browser.
Users of Metamask can store Ethereum and Ethereum Tokens in a secure manner, as well as interact with dApp’s.
Below is a further explanation of Metamask, how to install the extension for Google Chrome, and also how to add your Ethereum address to your Gemini account so that you can make withdrawals: