arc magma is likely to be at the expense of clinopyroxene (and/or olivine) by reaction-replacement. This reaction-replacement mechanism is effective at generating a ‘cryptic’ fractionation ...

For example, green olivine is very common in Hawaiian lavas ... volcano at the border between Queensland and New South Wales. Clinopyroxene crystals are often tiny, the size of a sand grain.

"It's possible that other crystals are being found," said Stovall, adding that a USGS rock specialist said olivine is difficult to tell apart from another common crystal, called clinopyroxene.