Sengierite

{{infobox mineral

| name = Sengierite

| category = Oxide and Hydroxide

| image = Sengierite-497485.jpg

| formula = Cu₂(OH)₂[UO₂{{Pipe}}VO₄]₂·6H₂O

| IMAsymbol = Sgi{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/imacnmnc-approved-mineral-symbols/62311F45ED37831D78603C6E6B25EE0A|journal=Mineralogical Magazine|volume=85|issue=3|pages=291–320|doi=10.1180/mgm.2021.43|bibcode=2021MinM...85..291W|s2cid=235729616|doi-access=free}}

| symmetry = Monoclinic 2/m

| color = Olive-green, yellowish green

| habit = Flattened thin plates, coatings

| system = Monoclinic

| cleavage = Perfect on {001}

| tenacity = Brittle

| mohs = 2.5

| luster = Adamantine, vitreous

| streak = Light green

| diaphaneity = Transparent

| gravity = 4.05

| density = 4.05 g/cm³ (measured)
4.1 g/cm³ (calculated)

| refractive = nα = 1.760 – 1.770 nβ = 1.920 – 1.940 nγ = 1.940 – 1.970

| pleochroism = X: Bluish green,
Y: Olive-green,
Z: Yellowish green to colorless

| 2V = Measured: 37° to 39°, Calculated: 36°

| other = 25px Radioactive

}}

Sengierite is a rare oxide and hydroxide mineral, chemically a copper and uranyl vanadate, belonging to the carnotite group. Its chemical formula is Cu₂(OH)₂[UO₂{{Pipe}}VO₄]₂·6H₂O.{{cite web|url=https://www.mindat.org/min-3620.html|website=mindat.org|title=Sengierite: Sengierite mineral information and data.|access-date=2018-08-09}}John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, and Monte C. Nichols, Eds., Handbook of Mineralogy, Mineralogical Society of America, Chantilly, VA 20151-1110, USA. [http://www.handbookofmineralogy.org/pdfs/sengierite.pdf PDF]

Sengierite was first discovered at the Luiswishi Mine about {{convert|20|km}} north of Lubumbashi in Katanga Province in the Democratic Republic of the Congo and was first described in 1949 by Johannes F. Vaes and Paul F. Kerr, the mineral was named after Edgar Sengier (1879–1963), a former director of the Union Minière du Haut Katanga.{{cite journal|author=J. F. Vaes |author2=Paul F. Kerr |year=1949|title= Sengierite: a preliminary description|journal=American Mineralogist|volume=34|pages=109–120|url=http://rruff.info/uploads/AM34_109.pdf}}