| Deposit ID | 10069083 |
|---|---|
| MRDS ID | W002385 |
| Record type | Site |
| Current site name | Fazenda Sitio De Coirana Amethyst |
| Geographic coordinates: | -42.46563, -14.29769 (WGS84) |
|---|
Political divisions (FIPS codes)
Bahia(province)
Brazil(country)
South America(continent)
Land(continent)
| Country | State |
|---|---|
| Brazil | Bahia |
| Commodity | Importance |
|---|---|
| Gemstone | Primary |
| Materials | Type of material |
|---|---|
| Amethyst | Ore |
| (1) | -42.46563, -14.29769 |
|---|
| Development status | Producer |
|---|---|
| Commodity type | Non-metallic |
| Significant | No |
| Agency | Database name | Acronym | Record ID | Notes |
|---|---|---|---|---|
| USGS | Mineral Resources Data System | MRDS | W002385 |
MONTHLY REPORT, BRAZIL PROJECT, MARCH 1969, HEDLUND, D.C
CIMRI
| Subject category | Comment text |
|---|---|
| Deposit | MOST MINERALIZATION IS IN ALTERED CHALLIS VOLCANICS ALONG FRACTURE ZONES TRENDING N 70 DEG E ON THE EAST FLANK OF THE BROAD ANTICLINE IN THE CHALLIS VOLCANICS |
| Deposit | QUARTZ VEIN AND GRAVEL LENSES |
| Deposit | AMETHYST QUARTZ IS BEING MINED FROM LATERITIC SOIL 4 TO 5 KM S.E. OF BREJINHO DAS AMETISTAS. THREE OCCURENCES IN THIS AREA ARE KNOWN, FAZENDAS SITIO DE COIRANA, SITIO VAI QUEM PODE, AND SAN MANOEL VIZENTO. THE WORKINGS ARE SMALL TUNNELS INTO CLIFFS OF LATERITE. GRAVEL LENSES WITH ROUNDED VEIN QUARTZ IN THE LATERITIC SOIL CONTAIN THE AMETHYST. THE SOIL IS AS MUCH AS 10 M THICK AND IS DERIVED FROM THE WEATHERING OF QUARTZITIC SANDSTONE DETRITUS OF THE SERRA CHAPADA DIAMANTINA. THE QUARTZITES OF THE SERRA ARE CUT BY NUMEROUS QUARTZ VEINS SOME OF WHICH CONTAIN AMETHYST. THE VEIN QUARTZ IS RESISTANT TO WEATHERING, WHEREAS THE QUARTZITE WEATHERS TO A FRIABLE SAND, AND DURING TRANSPORT THE VEIN QUARTZ COBBLES ARE CONCENTRATED IN LENSES WITHIN THE SANDY DETRITUS. |
| Type | Date | Name | Affiliation | Comment |
|---|---|---|---|---|
| Reporter | 01-MAY-1974 | Warfle, Thomas M. | U.S. Geological Survey |
Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.