 |
 |
Barry Jones asks: "Would the lead miner in the 18th, 19th century be able to tell the quality of Galena in a vein by its texture and colour. Galena seems to very in colour from bright silver to dull browns. A lot of galena lies around spoil heaps - tailings today which seems to have been disregarded by the miner or surface workers. " I wonder if the mineral found in the dumps, varying in colour from bright silver to dull browns, could be sphalerite, not galena? Looking in my copy of Rutley's Mineralogy (24th edition, revised by H.H. Read) I see that, under galena, the comment on colour gives only one shade, "lead-grey". It also says "there are apparently no external characters which serve to distinguish even the highly argentiferous ores from ordinary galena -- the question can only be solved by analysis". It also adds "galena often occurs with blende" Under "blende, sphalerite, black jack" the author states, regarding colour, that blende is "usually black or brown, sometimes yellow or white and, rarely, colourless". The miners would have tended to reject sphalerite as, until the retort method of extracting zinc was introduced, it would not have yielded any metal in a furnace, merely a cloud of white smoke up the chimney. Tony Brewis