THE MINERAL TSUMEBITE

  • Chemistry: Pb2Cu(PO4)(SO4)OH , Lead Copper Phosphate Sulfate Hydroxide
  • Class: Phosphates
  • Uses: only as a mineral specimen.
  • Specimens

Tsumebite forms good, colorful specimens and is a popular collection mineral, although quite rare. It is closely related to its cousin, arsentsumebite. The two minerals are in a series in which the arsenate ion group in arsentsumebite is replaced by a phosphate ion group in tsumebite. The two differ only slightly mostly because the structure is the same in the two minerals. Both are formed in the oxidation zone of lead-copper ore deposits.

Both minerals are unusual in that they have two ion groups instead of the usual one in most minerals. It the case of tsumebite, it has a phosphate ion group and a sulfate ion group. Mineralogists prefer to classify it as a phosphate because the phosphate ion group has a higher negative charge (-3) than the sulfate group (-2).

PHYSICAL CHARACTERISTICS:

  • Color is emerald green and yellow-green.
  • Luster is vitreous.
  • Transparency crystals are transparent to translucent.
  • Crystal System is monoclinic.
  • Crystal Habits include tabular crystals that can form twinned trillings and also as crusts and spherules.
  • Cleavage: None.
  • Fracture: Uneven.
  • Hardness is 3.5
  • Specific Gravity is approximately 6.2 (heavy for translucent minerals)
  • Streak is green.
  • Associated Minerals include azurite, wulfenite, mimetite, cerussite and smithsonite.
  • Notable Occurrences are limited to Tsumeb, Namibia and Morenci, Arizona, USA.
  • Best Field Indicators are crystal habit, locality, associations, density and color.
TSUMEBITE specimens:
(hover for more info)
TSUMEBITE specimen tsu-1
$ 39.00
Dims:2.2x1.4x0.9" (5.6x3.6x2.3 cm)
Wt: 1.7oz. (48g)
Mex-Tex Mine, Hansonburg Mining District, Socorro cty., New Mexico
Ose side of this specimen has a thin crust of silvery-green tsumebite crystals. These crystals are tiny-even with a loupe, one cannot distinguish the crystal form. Associated with the tsumebite are quartz, fluorite, and an unknown mineral that fluoresces bright yellow-green. The fluorite fluoresces blue. There is no damage to this specimen.
no photo
tsu-1 ($ 39.00)
Mex-Tex Mine, Hansonburg Mining District, Socorro cty., New Mexico
TSUMEBITE specimen tsu-2
$ 110.00
Dims:3.0x2.4x0.9" (7.6x6.1x2.3 cm)
Wt: 3.8oz. (109g)
Mex-Tex Mine, Bingham, Socorro cty., New Mexico
The matrix rock of this specimen is host to several tiny, but excellent crystals of tsumebite. They are a little too small to identify the monoclinic form, but they exhibit perfect faces when viewed under a loupe. Small vugs on either side of the specimen contain druses of quartz crystals, one heavily stained with iron, and one not. This is really a pleasure to view with a loupe. There is no damage to this specimen.
no photo
tsu-2 ($110.00)
Mex-Tex Mine, Bingham, Socorro cty., New Mexico
TSUMEBITE specimen tsu-3
$ 60.00
Dims:2.2x1.5x1.4" (5.6x3.8x3.6 cm)
Wt: 2.5oz. (70g)
Mex-Tex Mine, Hansonburg Mining Dist., Socorro cty., New Mexico
A large vug in this specimen is host to a layer of drusy quartz. On this drusy quartz is a thin layer of tsumebite crystals. These also occur on the top of the specimen as well. These crystals are tiny, and no details of the crystal form may be seen. There is only very minor damage to this specimen.
no photo
tsu-3 ($ 60.00)
Mex-Tex Mine, Hansonburg Mining Dist., Socorro cty., New Mexico
TSUMEBITE specimen tsu-4
$ 39.00
Dims:1.6x1.1x0.7" (4.1x2.8x1.8 cm)
Wt: 0.6oz. (18g)
Mex-Tex Mine, Socorro cty., New Mexico
Two sides of this specimen are coated with a thin crust of green tsumebite crystals. Accessory minerals are calcite and quartz. The tsumebite is crystalline-thousands of tiny crystal faces reflect the light. However, a 10-power loupe is insufficient to effectively study them. There is no apparent damage to this specimen.
no photo
tsu-4 ($ 39.00)
Mex-Tex Mine, Socorro cty., New Mexico

 


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