Stamps printed in excessive quantities
According to an article in the Philatelic Webmaster Organization, some companies that have printed stamps on behalf of poor countries (especially in Africa) are printed in excessive quantities aimed at collecting.
Stamps are only apparently approved by local postal administrations,
The article mentions in particular
many stamps and leaflets related to minerals, from countries such as:
Chad, Comoros, Mali, Niger, Congo ,
Burundi, Guinea Rep., Guiné Bissau Rep.,
Solomon Is., S.Tome & Prince, Togolaise Rep.....
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Black number = Scott catalog
Blue or red number = Yvert et Tellier catalog
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Scientists of Geosciences
| Image | Country | Year | Subject | Yvert | Set |
| | | | | | |
Meteorites
| Image | Country | Year | Subject | Yvert | Set |
| | | | | | |
Gems and Jewels FDC and Postcards
| NEW |  |
Garnet Precious stones |
Mongolia 2023 - n.c. Y&T - BF 439 |
 |
Various opals | |
| | Australia 2025 - n.c. Y&T - BF n.c. |
|
Tourmaline Garnet Spessartite Phenacite Scapolite |
 |
NEW |
Mocambique 2018- n-c. Y&T - BF 1254 |
Brasilianite Cassiterite Celestine Phosphophyllite |
 |
NEW |
Niger 2018- n-c. Y&T - BF 948 |
Monazite Spodumene Phenakite Euclase |
 |
NEW |
Niger 2018- n-c. Y&T - 4946-4949 |
Pyromorphite Dioptase Chalcantite Gold Gold |
 |
NEW |
Republique Cetrafricaine 2017- n.c. Y&T - 5241-5244 |
Apatite Celestine Garnet Grossulaire Rhodonite |
 |
NEW |
Republique Cetrafricaine 2019- n-c. Y&T - 6528-6531 |
Apophillyte Quartz Garnet Grossulaire (??) Apatite |
 |
NEW |
Republique de Djibouti 2019- n-c. Y&T - 2801-2804 |
2024 - n-c. Y&T - 1102 |
NEW | 2024 - n-c. Y&T - 1103 |
 |
Terre australes et antarctiques Francaises Epidote |
 |
| | 2022 Y&T 3075 |
|
Uruguay Quartz |
 |
NEW |
| | 1990 - 1331 |
|
| Zaire (Kinshasa) Gold |
 |
NEW |
Quartz |
 |
NEW |
FDC Bosna y Hercegovina 2025
|