The manufacturer’s exact-product evidence explicitly says not to use this product on granite, marble, or other listed surfaces, but does not explicitly address quartz.
Why
Quartz is not named as approved, and the product is a cleanser/polish with unknown chemistry. Given the manufacturer’s prohibition on several stone surfaces, compatibility with quartz cannot be established for normal use.
What to do
Do not use on quartz unless the quartz manufacturer specifically confirms compatibility. Use a quartz-approved cleaner instead.
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 ↗