Solidity smart contracts operate in a hostile environment, which introduces the need for the adequate application of testing techniques to ensure mitigation of the risk of a security incident. Mutation testing is one such technique. It allows for the evaluation of the efficiency of a test suite in detecting faults in a program, allowing developers to both assess and improve the quality of their test suites. In this paper, we propose a mutation testing framework and implement a prototype implementation called Vertigo that targets Solidity contracts for the Ethereum blockchain. We also show that mutation testing can be used to assess the test suites of real-world projects.