Approximate computing is a design paradigm considered for a range of applications that can tolerate some loss of accuracy. In fact, the bottleneck in conventional digital design techniques can be eliminated to achieve higher performance and energy efficiency by compromising accuracy. In this letter, a new architecture that engages accuracy as a design parameter is presented, where an approximate parallel multiplier using heterogeneous blocks is implemented. Based on design space exploration, we demonstrate that introducing diverse building blocks to implement the multiplier rather than cloning one building block achieves higher precision results. We show experimental results in terms of precision, delay, and power dissipation as metrics and compare with three previous approximate designs. Our results show that the proposed heterogeneous multiplier achieves more precise outputs than the tested circuits while improving performance and power tradeoffs.