The Klinker occurrence is situated in the northern headwaters of McGregor Creek, approximately 2.4 kilometres northeast of Hailstone Mountain and 23 kilometres west-northwest of Vernon.
Regionally the area is underlain by volcanics, mudstone, siltstone, shale and fine clastic sedimentary rocks of the Devonian to Triassic Harper Ranch and(?) Nicola groups, which are intruded by Middle Jurassic granitic rocks. Extensive volcanic and sedimentary rocks of the Eocene Kamloops and Penticton groups overlie the older units.
The area contains several concentrations of precious opal developed in the basal 100 metres of the Kamloops Group. The hostrock is a volcanic breccia-lahar complex composed of angular to rounded clasts of andesite and basalt ranging from 0.2 to 0.6 metre in diameter in a lapilli tuff matrix. In the lahar, the tuff has bedding that swirls around the clasts. Lapilli tuff lenses up to 5 metres thick develop locally and indicate that the volcanic succession dips 20 to 30 degrees to the west. Thin andesite or basalt flows and intrusions up to 4 metres thick are scattered throughout. On McGregor Creek Forestry Access Road, approximately 500 metres east of the discovery pit, outcrops of grey-green probable Late Paleozoic meta-andesite flows and lapilli tuffs form the basement, which dips gently westward and underlies the valley bottom of Ewer Creek north of the property.
Locally, precious opal, agate and common opal fill fractures in the Eocene rocks and permeate podiform rock masses that are up to 0.5 metre in diameter in the lahars. The rock masses are smaller in the lapilli tuffs and absent in the flows or intrusions. Precious opal-filled fractures preferentially develop in sets with the following three preferred strikes: 025 ± 10 degrees, 070 ± 10 degrees and 330 ± 15 degrees; all sets have steep dips. The podiform rock masses commonly form beside or across opal-filled fractures. In the masses, precious opal fills voids developed during the formation of the hostrock, and later openings apparently formed by local dissolution of the host. Here and there the precious opal, agate and common opal have layering that is subhorizontal, even in subvertically oriented fracture fillings. The presence of subhorizontal layering in these materials, which is not subparallel to the orientation of the gently west-dipping lapilli tuff, implies that the precious opal, agate and common opal precipitated after the beds were tilted.
Of the numerous shallow pits exposing the precious opal on the Klinker property, the discovery pit is the largest at 2100 square metres and, together with the smaller Bluebird pit, probably the richest because of subequally developed podiform masses and fracture fillings. A right-lateral strike-slip fault dips 80 degrees northwest (slickensides trend/plunge 195/25S), passes along the eastern side of the pit and offsets the lahars an indeterminate amount. In the other shallow pits, referred to as the Tripod, Red Rock, East Waterhole, Caramel and Caramel Extension, podiform masses in the lahars developed at the expense of fracture fillings. A lapilli tuff underlies the eastern side of the Caramel pit. Outside the pit areas, the primary openings of the rock are either mostly empty or less commonly filled with agate, common opal, chabazite—a highly hydrated zeolite—and other unidentified zeolites (P. Read, personal communication, 1995).
The opal is white, orange or red, with some fire-green and fire-orange opal reported. Most of the precious opal is described as having a light-orange base, and is clear and full of colour. At surface the opal is hydrophane but becomes more solid at shallow depths. The banded agate has grey, white and clear bands.
Besides precious opal, common opal and agate, other fracture-fill minerals include non-precious facet-grade opal, quartz, celadonite, amorphous manganese oxides, clinoptilolite, heulandite, stilbite, jarosite, clays and, rarely, calcite . Non-precious, facet-grade opal is typically orange and honey coloured, similar to Mexican ‘fire opal’. Common opals occur as transparent, translucent and opaque types in white, honey, brown, amber, orange and grey. Quartz can occur as small, inward-facing, terminated crystals within vugs. X-ray diffraction analysis notes that kutnahorite and saponite co-exist with opal. Opal from the Klinker property is classified as opal-CT, using Jones and Segnit's (1971) grade classification. Most stones from deposits with precious and common opal are classified as opal-A (Frye, 1981).
The opal occurrence was discovered in 1991, and by 1994 there was enough volume of commercial grade opal excavated during the 1994 season's bulk sampling program to provide the raw material necessary to start a small-scale gemstone cutting and retail sales business. Sorting, grading and cutting of finished gemstones began on a limited scale in November 1994 and continued through to late December 1994. This program recommenced on January 1, 1995 and was scheduled to produce enough quality and quantity of finished 'opal product' to support a local retail sales operation by May 1, 1995 (Assessment Report 24606).
Small-scale test mining and marketing by Okanagan Opal Inc. was performed in 1996 (Information Circular 1996-1, page 20). Okanagan took a 316.5-tonne bulk sample of opal-bearing material from test pits. The company set up a workshop and retail outlet in Vernon, where opal jewellery and specimens were produced and sold. During 1995 through 2003, approximately 500 tonnes of opal-bearing material was removed and processed.
In 2010, Opal Resources Canada Inc. produced fire opal gemstones and jewellery from the Klinker property (Exploration and Mining in BC 2010). In 2017 and 2018, programs of prospecting, geological mapping, geochemical sampling and trenching were performed on the area as the Klinker/Ewer property. Also during this time, approximately 6 tonnes of opal-bearing material was hand sorted from existing stockpiles.
