{"topic":"tetradymite","count":1,"articles":[{"id":"britannica-11-tetradymite","work_id":"britannica-11","title":"Tetradymite","normalized_title":"tetradymite","slug":"tetradymite","aliases":[],"subtitle":"Internet Archive OCR import","body_text":"TETRADYMITE, a mineral consisting of bismuth telluride and sulphide, Bi2Te2S, also known as \" telluric bismuth.\" Sometimes sulphur is absent and the formula is then Bi2Tes; traces of selenium are usually present. Crystals are rhombohedral, but are rarely distinctly developed; they are twinned together in groups of four; hence the name of the mineral, from the Greek, T«Tpa50/^js, fourfold. There is a perfect cleavage parallel to the basal plane; and the mineral usually occurs in foliated masses of irregular outline. The colour is steel-grey, and the lustre metallic and brilliant. The mineral is very soft (H=i£) and marks paper; the specific gravity is 7-2 to 7-6. It was first found, in 1815, at Telemarken in Norway; crystals are from Schubkau near Schemnitz in Hungary. It often occurs in quartz associated with native gold. Other species very similar to tetradymite, but with different formulae, are: joseite, from San Jose near Marianna in Brazil; grunlingile (Bi4S3Te), from Caldbeck Fells in Cumberland; and wehrlite, from Hungary. (L. J. S.)","body_html":"<p>TETRADYMITE, a mineral consisting of bismuth telluride and sulphide, Bi2Te2S, also known as &quot; telluric bismuth.&quot; Sometimes sulphur is absent and the formula is then Bi2Tes; traces of selenium are usually present. Crystals are rhombohedral, but are rarely distinctly developed; they are twinned together in groups of four; hence the name of the mineral, from the Greek, T«Tpa50/^js, fourfold. There is a perfect cleavage parallel to the basal plane; and the mineral usually occurs in foliated masses of irregular outline. The colour is steel-grey, and the lustre metallic and brilliant. The mineral is very soft (H=i£) and marks paper; the specific gravity is 7-2 to 7-6. It was first found, in 1815, at Telemarken in Norway; crystals are from Schubkau near Schemnitz in Hungary. It often occurs in quartz associated with native gold. Other species very similar to tetradymite, but with different formulae, are: joseite, from San Jose near Marianna in Brazil; grunlingile (Bi4S3Te), from Caldbeck Fells in Cumberland; and wehrlite, from Hungary. (L. J. S.)</p>","volume_id":"britannica-11-v26","page_range_label":"Vol. 26, pp. 670-670","source_url":"https://archive.org/details/encyclopaediabri26chisrich/page/n713/mode/1up","text_source_url":"https://archive.org/download/encyclopaediabri26chisrich/encyclopaediabri26chisrich_djvu.txt","scan_source_url":"https://archive.org/details/encyclopaediabri26chisrich","quality_status":"ocr-imported-page-aligned","parser_version":"ia-djvu-xml-v1","page_refs":[{"page_number":"670","label":"p. 670","image_url":"/source-assets/scans/britannica-11/encyclopaediabri26chisrich/encyclopaediabri26chisrich_0714.jpg","source_image_url":"https://archive.org/download/encyclopaediabri26chisrich/encyclopaediabri26chisrich_jp2.zip/encyclopaediabri26chisrich_jp2%2Fencyclopaediabri26chisrich_0714.jp2&ext=jpg","source_url":"https://archive.org/details/encyclopaediabri26chisrich/page/n713/mode/1up"}],"work":{"id":"britannica-11","slug":"britannica-11","title":"Encyclopaedia Britannica","short_title":"Britannica 11th","edition":"11th edition","publisher":"Cambridge University Press","publication_start_year":1910,"publication_end_year":1911,"language":"English","country":"United Kingdom / United States","copyright_status_note":"First published before 1931; treated as public domain in the United States. Verify jurisdiction before redistribution outside the U.S.","source_quality":"mixed-clean-and-ocr","text_source_url":"https://en.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica","scan_source_url":"https://archive.org/details/encyclopaediabri","volumes":[{"id":"britannica-11-v1","volume_number":"1","title":"A to Androphagi","year":1910,"source_url":"https://archive.org/details/encyclopaediabri01chisrich","text_source_url":"https://en.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica","scan_source_url":"https://archive.org/details/encyclopaediabri01chisrich","page_count":1084},{"id":"britannica-11-v2","volume_number":"2","title":"Andros to Austria","year":1910,"source_url":"https://archive.org/details/encyclopaediabri02chisrich","text_source_url":"https://archive.org/download/encyclopaediabri02chisrich/encyclopaediabri02chisrich_djvu.txt","scan_source_url":"https://archive.org/details/encyclopaediabri02chisrich","page_count":null},{"id":"britannica-11-v9","volume_number":"9","title":"Edwardes to Evangelical Association","year":1910,"source_url":"https://archive.org/details/encyclopaediabrit09chisrich","text_source_url":"https://archive.org/download/encyclopaediabrit09chisrich/encyclopaediabrit09chisrich_djvu.txt","scan_source_url":"https://archive.org/details/encyclopaediabrit09chisrich","page_count":null},{"id":"britannica-11-v26","volume_number":"26","title":"Submarine Mines to Tom-Tom","year":1911,"source_url":"https://archive.org/details/encyclopaediabri26chisrich","text_source_url":"https://archive.org/download/encyclopaediabri26chisrich/encyclopaediabri26chisrich_djvu.txt","scan_source_url":"https://archive.org/details/encyclopaediabri26chisrich","page_count":null},{"id":"britannica-11-v27","volume_number":"27","title":"Tonality to Vesuvius","year":1911,"source_url":"https://archive.org/details/encyclopaediabri27chisrich","text_source_url":"https://ia903207.us.archive.org/15/items/encyclopaediabri27chisrich/encyclopaediabri27chisrich_djvu.txt","scan_source_url":"https://archive.org/details/encyclopaediabri27chisrich","page_count":null}]}}]}