The manufacturer explicitly says not to use this product on granite; quartz is an engineered stone commonly containing quartz and resin, but the evidence does not establish compatibility with it.
Why
The product is prohibited on granite and marble, and quartz is not explicitly approved. This cleanser/polish may contain abrasive or otherwise unsuitable chemistry for quartz surfaces.
What to do
Do not use on quartz based on the provided manufacturer evidence; choose a cleaner specifically approved for quartz.
pH
Not stated in provided evidence.
Relevant chemistry
Chemistry is not established by the provided evidence. Intended to clean and polish most hard, nonporous surfaces.
Source: official product page ↗