The Sapphire Hill occurrence is located on the Blu Starr gemstone property, near the community of Vallican. The Blu Starr property is situated at the confluence of the Slocan and Little Slocan rivers near Passmore, approximately 25 kilometres west of Nelson.

The Slocan Blu Starr property lies within the southern portion of the Valhalla-Passmore Gneiss Complex, in the Passmore Dome. The Valhalla Complex consists of a high-grade metamorphic core with outwardly dipping metamorphic layering and foliation. Heterogeneous sequences of biotitic schist (pelitic schist), quartzo-feldspathic gneiss (psammitic gneiss), amphibolite gneiss, and minor marble, calc-silicate gneiss, quartzite, metaconglomerate and ultramafic rocks make up the Valhalla assemblage of metamorphic rocks.

The Sapphire Hill occurrence is the largest exposed area of sapphire mineralization on the Blu Starr property. In all, 16 sapphire occurrences are found within an amphibolite-rich rock approximately 50 metres thick, along a strike of 1.5 kilometres. The sapphires occur in well-exposed crosscutting plumasite dikes and in the gneiss in the adjoining wall rock. Sapphires on the Blu Starr property have been identified as the star sapphire variety and are semitranslucent grey-blue to bronze-black in colour.

Plumasite dikes form as either sill-like structures cutting metamorphic rocks at a low angle or as sinuous dikes with a general strike direction of 110 degrees. These dikes can be traced for tens of metres along strike and rarely exceed 1 metre in width. The geology at Sapphire Hill is almost identical in both lithology and metamorphic grade to the New Star, Iolite and Blu Starr sapphire occurrences. The Blu Starr, New Star and Sapphire Hill occurrences appear to be at least partially stratigraphically controlled, forming both within and proximal to plumasite dikes intruding shallow-dipping mafic gneiss. These occurrences have been interpreted to represent exposed and inferred mineralized zones of greater than 6 kilometres, with potential for expansion.

The Blu Starr sapphire deposit was discovered in 1991, followed by the discovery of the Blu Moon sapphire deposit (MINFILE 082FNW263) to the northwest in 1993. From 1991 to 1995, approximately 10 tonnes of sapphire-bearing rock was hand mined, yielding approximately 10 kilograms (50 000 carats) of coarse rough sapphire from Blu Starr and 1 kilogram (5000 carats) from Blu Moon (Press Release, Anglo Swiss Resources Inc., December 18, 2012). The property was acquired by Anglo Swiss Resources Inc. in 1995. That same year, Marylou Coyle, PhD, was contracted to study the deposits and make recommendations for development. In 1996, the first organized geological studies of sapphire deposits were conducted, leading to the discovery of aquamarine beryl crystals in quartz-tourmaline pegmatitic dikes. In 1997, a 150 tonne composite bulk sample was extracted from the Blu Moon deposit and sent for processing. Smaller hand samples were taken from Blu Starr and other gem showings on the property. In 1998, a small gem garnet deposit was discovered on a mountainside near the Blu Starr deposit and a 2-tonne bulk sample was extracted. That same year, an extensive mineralized zone of crystalline graphite was discovered in the Tedesco area and the Sapphire Hill occurrences were found near the Blu Moon deposit. Three zones of iolite mineralization were also found north of the Blu Starr deposit in the fall of 1998. One tonne of sapphire-mineralized rock was extracted from Sapphire Hill and two 1 tonne bulk samples containing approximately 25 kilograms of coarse rough crystal and gem iolite were extracted from the I1 and I2 iolite zones. In 1999, a detailed geological examination of the iolite zones was completed.

In 2000, Hampton Court Resources partnered with Anglo Swiss Resources in a joint venture. Exploration by Hampton Court focused on evaluating the potential of placer claims along the Slocan River, west of the Blu Starr deposit. The potential of alluvial deposits along the Slocan Valley was assessed with respect to potentially commercial deposits of gemstones, including garnet, iolite and sapphire. Work that year consisted of 8.5 kilometres of ground-penetrating radar, surface geological mapping and preparation of a report titled Mineralogic Evaluation of the Slocan River Placer Claims. At the same time, exploration continued on other areas of the property. Thirteen new sapphire occurrences were identified, as were occurrences of amethyst quartz, rose quartz and titanite. Ten new iolite-anthophyllite occurrences were discovered along the Rainbow Horizon, and the New Star claim was staked to cover the northern extension of the iolite-anthophyllite–bearing Rainbow Horizon. A potentially large and economic gem garnet occurrence was identified in the Tedesco area. Bulk samples were extracted from the Tedesco garnet deposit (2.76 tonnes) and the I1 Iolite deposit (greater than 100 tonnes). More than 1000 carats of red garnet gem rough were recovered from Tedesco and more than 5 tonnes of specimen crystal and coarse rough gem material were recovered from the I1 Iolite (Assessment Report 26537).

In 2003, the joint venture with Hampton Court lapsed. Work on the property was suspended until 2008, when a graphite exploration program was undertaken. Ground geophysics was used to explore for graphite up to 200 metres in depth. Three diamond drill holes totalling 812.9 metres were completed. In 2010, 525.9 kilometres of airborne geophysical surveys were completed across the entire property. A limited ground survey of soil sampling and prospecting was carried out on the region of known graphite occurrences. In 2012, an induced polarization survey was carried out over the Tedesco graphite showing.

Approximately 3 kilograms of blue-grey and bronze-black sapphire were extracted from approximately 1 tonne of mineralized rock taken from Zone 1 and Zone 1A. A 20-kilogram float boulder from Zone 1A yielded over 1.2 kilograms (6000 carats) of blue and grey sapphire. The largest crystals were over 20 grams (100 carats) in size. Several star cabochons and one dark blue 0.5 carat brilliant sapphire were also cut from the float boulder (Press Release, Anglo Swiss Resources Inc., December 18, 2012).