3.5" Cerussite Crystals on Botryoidal Hemimorphite - Congo

This is a lustrous formation cerussite crystals on blue botryoidal hemimorphite. This specimen was collected from M'fouati in the Bouenza Department of the Republic of the Congo. The base of this specimen has been cut flat for presentation.

Hemimorphite is a basic hydrous zinc silicate with the chemical composition Zn4Si2O7(OH)2 · H2O. It earned its name from the structure of which the crystals form, through greek terminology. It has two different terminations on each side of the crystal, hence the inclusion of the greek terms "hemi", meaning half and "morph", meaning shape. The crystal formations can range anywhere between a crystal druze or botryoidal formation, to radiating acicular crystals, and more. The color of these crystals have been found to be white, beige, light brown and blue. On rare occasions, yellow and green crystals have been found.

Prior to 1803, hemimorphite and smithsonite were thought to be the same mineral called "calamine". However, following further scientific research, it was concluded that these were two distinct minerals.

Cerussite is a carbonate mineral with the chemical formula PbCO3, and is an important ore of lead. This lead-carbonate consisting mineral is a common weathering product of galena, explaining why it is typically extracted from oxidized zones of lead ore deposits. It can form into a variety of different structures, sometimes in fibrous patterns, other times in granular aggregations, though generally forming vitreous pseudo-hexagonal crystals. The colors of this mineral vary depending on composition and structure, with colorless, white, grey and green tinted, being the most common colors of crystals found.
DETAILS
SPECIES
Hemimorphite & Cerussite
LOCATION
M'fouati, Bouenza Department, Republic of the Congo
SIZE
3.5 x 2.2"
SUB CATEGORY
ITEM
#148437