THE MINERAL COLLINSITE

  • Chemistry: Ca2(Mg, Fe)(PO4)2 - 2H2O, Hydrated Calcium Magnesium Iron Phosphate.
  • Class: Phosphates
  • Group: Fairfieldite
  • Uses: Mineral specimens.
  • Specimens

Collinsite is a relatively rare and not well known phosphate mineral. It forms in nodules and as crusts in altered granite pegmatites. Crystals tend to be prismatic and are often aggregated together into bundles.

PHYSICAL CHARACTERISTICS:

  • Color is brown to white or colorless.
  • Luster is vitreous.
  • Transparency: specimens are translucent to less commonly transparent.
  • Crystal System: is triclinic; bar 1
  • Crystal Habits include nodules and crusts in altered granite pegmatites. Crystals tend to be prismatic and are often aggregated together into bundles.
  • Cleavage is perfect in one direction.
  • Fracture is uneven.
  • Hardness is 3.5.
  • Specific Gravity is approximately 3.0 (average for translucent minerals)
  • Streak is off white.
  • Notable Occurrences: Tip Top Mine, Custer Co., South Dakota, USA, Francois Lake, British Columbia, Canada and at other localities.
  • Best Field Indicators: color, crystal habit, hardness and localities.
COLLINSITE specimens:
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COLLINSITE specimen cln-1
$ 200.00
Dims: 2-3/8" x 1-1/2" x 1-1/4"
Wt: 2.0 oz
Rapid Creek, Yukon, Canada
I really don't have much to say about this mineral; it is relatively nondescript, and doesn't exhibit any unusual properties like fluorescence or phosphorescence. Basically, the specimen consists of gray-white radial blades of Collinsite on what appears to be a basalt matrix. The structure of the clusters of this mineral remind me just a bit of that of Moroccan barite specimens that I have seen. These clusters exceed 1/2 inch in diameter and have a waxy luster that is almost dull in some areas. The radial structure is intriguing, though, and the blades and their terminations are delicate. The most redeeming quality, though, is likely to be the material's rarity.
no photo
cln-1 ($200.00)
Rapid Creek, Yukon, Canada
COLLINSITE specimen cln-2
$ 160.00
Dims: 2.5 x 2.1 x 1.5" (6.4 x 5.3 x 3.8 cm)
Wt: 5.40 oz. (153.0 g)
Rapid Creek, Yukon, Canada
A thin crust of Collinsite partly coats the gray-and-white host rock of this specimen. The crust is made up of several intergrown clusters, and each cluster in turn is made up of anywhere from 10 to 50 Collinsite blades. These blades do not exceed 0.3" (8 mm) in length, and are generally in good condition, though a few of the clusters are broken and incomplete. Their triclinic form is good, as their intense intergrowth has slightly warped their shapes. All have moderately well-defined edges and striated but clean faces that possess a pearly luster. All have a subtle, gray-green coloration and are generally translucent, though some individual crystals show visible transparence. The host rock on which they rest is dark gray in color and rather dense, making me think that it contains a substantial amount of iron. It is partly coated with a very thin, dull white crust that is microcrystalline in nature.
no photo
cln-2 ($160.00)
Rapid Creek, Yukon, Canada
COLLINSITE specimen cln-3
$ 66.00
Dims: 2.2 x 2.1 x 1.1" (5.6 x 5.4 x 2.7 cm)
Wt: 3.8 oz. (107 g)
Boundary Creek, near Yukon, Northwest Territory, Canada
This specimen consists entirely of a crust of compact, crystalline Collinsite. A few hollows in the crust hold clusters of Collinsite needles that reach 0.2-0.3" (5-8 mm) in length and are generally in good condition. All have good triclinic form and a pearly luster. All of the Collinsite has a more or less uniform pale green color, though the actual exposed crystals are pale and somewhat grayer in color. Apart from thin brown skins on either side of the crust, there is no host rock present.
no photo
cln-3 ($ 66.00)
Boundary Creek, near Yukon, Northwest Territory, Canada
COLLINSITE specimen cln-4
$ 53.00
Dims: 2.7x1.4x1.1" (6.8x3.5x3.1 cm)
Wt: 1.99 oz. (56.2g)
Rapid creek, Yukon, Canada
This finger specimen is about half collinsite, half host rock. The collinsite appears as heavily intergrown pale green prismatic crystals, and in some places shows a radial habit. Many of the crystals are undamaged and show excellent form. Others are broken or had their growth limited by the next rock over (the host rock looks like a fine black shale that became separated into layers with gaps enabling the collinsite crystals to grow).
no photo
cln-4 ($ 53.00)
Rapid creek, Yukon, Canada
COLLINSITE specimen cln-5
$ 30.00
Dims: 1.5x0.7x1.1" (3.8x1.8x2.8 cm)
Wt: 0.5 oz. (14.0g)
Rapid Creek, Yukon, Canada
This collinsite specimen consists of several radiating clusters of pale green prismatic crystals on a black host rock. The crystals appear transparent under a loupe, although a rough surface luster lends more of a translucent appearance.
no photo
cln-5 ($ 30.00)
Rapid Creek, Yukon, Canada

 


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