The Cheryl opal occurrence is located between Vidler and Mosquito creeks, approximately 13 kilometres south east of Lumby.

Agate, common opal and some minor precious opal are found along Mosquito Road for a distance of about 150 metres, and in a cliff about 800 metres south of the first showing. Locally, chalcedony occurs as fracture fillings within Eocene rhyolite and dacite lava flows and laharic ash flows.

In 1997, samples collected included translucent to milky agate, smokey and blue quartz, white and light blue common opal, and minor blue opal with red, honey and amber flashes of colour (Assessment Report 25741).