Harp rhodonite occurrence, Kaslo, Slocan Mining Division, British Columbia, Canadai

Regional Level Types
Harp rhodonite occurrence	Occurrence
Kaslo	Village
Slocan Mining Division	Division
British Columbia	Province
Canada	Country

Latitude 049º 55' 08'' North; Longitude: 116º 58' 28'' West. The Harp rhodonite occurrence lies to the east of the Kaslo River valley, east of the abandoned settlement of Zwicky, about 5 kilometres west-northwest of the Village of Kaslo, and 54 kilometres north-northeast of Nelson, British Columbia.
Note that the location data presently given on Minfile seem incorrect. They were probably derived by reference to the location cited by early workers as about 5 miles from Kaslo. The old CPR Railway Station of Zwicky is mentioned but seems not to appear on most maps of the area. However, the station is shown, at the mouth of Keen Creek (South Fork, Kaslo River), on a map in Turner and Wilkie (1994, p. 52). Cairnes (1935) gave the location as “. . . less than a mile east of, and about 350 feet above, Zwicky. Confirmation of the location is provided by reference to a geologic map in Lee (1988, part 2, Figure 6). I have provided location data based on this map.
This is the second of four deposits or occurrences with significant manganese contents, either within the deposits themselves or in the surrounding rocks. These lie in a northwesterly belt about 25 kilometres long, generally along the valley of the Kaslo River; the others are (from north to south): the True Blue polymetallic deposit to the south; the Zwicky manganese mine; and the Contact (Black Prince) polymetallic occurrence.
Giles Peatfield comments:
There is a very brief description of the occurrence, listed as a showing, on the British Columbia “Minfile” site, current to 1985. A relevant portion of this description is quoted below:
“A series of quartz veins occur in sedimentary rocks or along the contact of sediments with greenstone schist of the Lower Permian Kaslo Group. The footwall rock of one vein was explored by a short adit. It consists of a greenish schist carrying abundant rhodonite in lens-like masses from 5 to 45 centimetres wide, adjacent to the quartz vein. The hangingwall is a quartzitic argillite containing manganiferous garnet, partly altered to manganese oxide.
The veins consist of vitreous to smoky quartz mineralized with pyrrhotite, pyrite and chalcopyrite.”
Detailed mapping in the Harp occurrence area (Lee, 1988) suggests that the occurrence lies at or near the indistinct contact of the older Milford Group (dominantly sedimentary) and the overlying Kaslo Group (dominantly volcanic rocks).
There is no official record of production from this prospect; workings consisted of trenches and a short adit. Note that rhodonite is an important gem mineral, with many sources in British Columbia. Although there is no obvious record of exploitation of the mineral from this locality, it was mentioned as a mineral occurrence or collecting locality by: Sabina (1964), Traill (1970, 1983), and Leaming (1973).

Giles Peatfield Comments on the Minerals Reported:
“Wad”: Describing the quartz vein with rhodonite, Bancroft (1918) wrote that “A small amount of manganese oxide in the form of wad is mixed with rhodonite in the vein.”
Amphibole group: Leitch (1988) described, in thin section from a sample in the area of the rhodonite occurrence, tremolite that is “. . . almost colourless, with amphibole cross-sections and extinction angles of around 15 degrees.”
Calcite: Bancroft (1918) noted that “Eugene Poitevin, of the Geological Survey, reports on a specimen submitted to him, as follows: ‘It consists of calciferous rhodonite, that is, impure rhodonite, due to the presence of calcium and iron carbonate.’ ”
Chalcopyrite: Bancroft (1918) wrote that in the rhodonite-bearing vein “The gangue consists of vitreous smoky quartz, carrying pyrrhotite, pyrite, and chalcopyrite. These sulphides impregnate the wall rock and cause the foot-wall in particular to weather to a rusty brown.” Langley (1919) reported ‘small quantities’ of pyrite, pyrrhotite and chalcopyrite. According to Cairnes (1932) the quantities of these minerals was ‘variable’.
Chlorite group: Bancroft (1918) described the footwall of the rhodonite-bearing vein as ‘chlorite schist’. Mapping by Lee (1988) showed the Kaslo Group rocks in the area of the rhodonite occurrence – see note below for rhodonite – to be “Green fine grained porphyritic andesitic volcanics and dacitic intrusions, often strongly sheared and altered to chlorite.”
Garnet group: Cairnes (1932) described the hanging-wall of a rhodonite-bearing vein as “. . . a banded quartzitic argillite composed chiefly of quartz and a manganiferous garnet which is partly altered to oxide of manganese.” Cairnes (1935) described a thin section of this rock as “. . . a mosaic chiefly of quartz and a manganiferous garnet, the latter partly altered to oxide of manganese.” Leitch (1988) presented two SEM analyses of garnets from the showing area, both of which are shown to be Mn-rich garnet (spessartine). Note that Leitch’s second garnet spectrum has the Mn peak (apparently) mis-labelled as Fe.
Graphite?: Bancroft (1918) described a ‘somewhat graphic [sic – graphitic?] schist’ in the hanging-wall of the main vein. Cairnes (1932) described ‘graphite (or pyrolusite)’, and later (1935) described pyrolusite in thin section. I regard graphite as tentative here.
Magnetite: Leitch (1988) described, from a sample in the area of the rhodonite occurrence, “Dark patches visible in hand specimen [that] are sometimes magnetic; in thin section these are [seen to be] aggregates of fine (0.03 mm) magnetite grains.”
Mica group: Cairnes (1932) noted that the sulfide-bearing veins “. . . consist of vitreous to smoky quartz with considerable sericite, . . . .”
Pyrite: See note above for chalcopyrite.
Pyrolusite: See note above for graphite?, and below for rhodonite.
Pyrrhotite: See note above for chalcopyrite.
Quartz: See note above for mica group.
Rhodonite: This is the mineral of most interest at the Harp showing. Bancroft (1918) described the occurrence as follows: “The rhodonite in the vein is massive, dull grey to deep pink in colour. It occurs along the foot-wall in fairly continuous bunches which were probably at one time joined together in a continuous band of rhodonite varying in width up to 18 inches.” Cairnes (1935) noted that “Under the microscope the rhodonite-bearing rock much resembles a siliceous limestone and is composed of quartz, calcite, a little garnet, considerable pyrolusite, and abundant rhodonite. The latter occurs in masses, streaks, and disseminations through the rock, in places reaching a width of several inches.” The locality was mentioned by Sargent (1956) and by Johnston and McCartney (1965), but with little new information. See also comments above for “wad” and for calcite.
Siderite?: See note above for calcite – presumably the ‘iron carbonate’ is siderite.
Tourmaline group: Leitch (1988) reported that tourmaline from the Harp showing area was shown by SEM analysis to be the “. . . pale yellow Mg-rich [variety] dravite (confirmed by SEM study).”
Giles Peatfield Comments on the Rock Types Reported:
Based on detailed mapping in the area of the Harp occurrence (Lee, 1988), it seems that the argillite, schist and limestone are parts of the older Milford Group, whereas the andesite and dacite are parts of the overlying Kaslo Group. See also Fyles (1967).

Giles Peatfield
BASc. (Geological Engineering) University of British Columbia 1966.
PhD Queen's University at Kingston 1978.
Worked for Texas Gulf Sulphur / Texasgulf Inc. / Kidd Creek Mines - 1966 to 1985.
Consultant 1985 to 2016

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Link to British Columbia Minfile:	082FNE152

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References