THE MINERAL ALMANDINE

  • Chemistry: Fe3Al2(SiO4)3, Iron Aluminum Silicate
  • Class: Silicates
  • Subclass: Nesosilicates
  • Group: Garnets
  • Uses: Gemstone and abrasive
  • See our natural Almandine Mineral Specimens
    For Garnet Jewelry, see: GARNET JEWELRY

Almandine is the most common of the garnets and is usually the garnet found in garnet schists (a type of metamorphic rock composed mostly of mica). Precious transparent crystals are frequently used as gemstones along with its close cousin, Pyrope. Almandine, like other garnets, forms rounded crystals with 12 rhombic or 24 trapezoidal faces or combinations of these and some other forms. This crystal habit is classic for the garnet minerals. Almandine is the iron aluminum garnet. Magnesium can substitute for the iron and become more like pyrope, the magnesium aluminum garnet. Pure almandine and pure pyrope are rare in nature and most specimens are a percentage of the two. The change in density from almandine (4.3) to pyrope (3.6) is the only good test to determine a specimens likely identity.

PHYSICAL CHARACTERISTICS:

  • Color is typically red to brown, sometimes with a tinge of purple and sometimes a deep enough red to appear black.
  • Luster is vitreous.
  • Transparency crystals are transparent to translucent.
  • Crystal System is isometric; 4/m bar 3 2/m
  • Crystal Habits include the typical rhombic dodecahedron. also seen is the 24 sided trapezohedron. Combinations of these forms are common and sometimes the rare faces of the hexoctahedron, a 48 sided crystal habit that rarely is seen by itself, can also combine with these other forms making very attractive, complex and multifaceted crystals. Massive occurrences are also common. Crystals typically embedded and isolated, from other alamadine crystals, in metamorphic rocks.
  • Cleavage is absent.
  • Fracture is conchoidal.
  • Hardness is 6.5 - 7.5
  • Specific Gravity is approximately 4.3 (above average for translucent minerals and the highest density of all garnets)
  • Streak is white.
  • Associated Minerals are micas, staurolite, quartz and feldspars.
  • Other Characteristics: index of refraction is 1.83 and multiplicity of faces give a striated appearance on some crystals.
  • Notable Occurrences include Wrangel Alaska; Germany; Norway and India.
  • Best Field Indicators are crystal habit, color, density and hardness.
ALMANDINE specimens:
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ALMANDINE specimen alm-1
$ 72.00
Dims: 5-1/2" x 4" x 1"
Wt: 14 oz
Wrangell, Alaska, U.S.A.
This excellent specimen from the far north is a classic occurrence for Almandine Garnet: wrapped in layers of Mica schist. It has two complete Garnets, each measuring about to 1 inch in diameter, and two broken crystals. These are very popular among collectors, but they cannot be dug up by them. The owner of the mine bequeathed it to the children of Wrangell, Alaska, who are the only ones allowed to harvest the high-qualtiy crystals.
no photo
alm-1 ($ 72.00)
Wrangell, Alaska, U.S.A.
ALMANDINE specimen alm-2
$ 105.00
Dims: 5" x 3-3/4" x 2-1/4"
Wt: 1 lb., 4 oz
Wrangell, Alaska, U.S.A.
There are four Almandine Garnets immediately visible in this Alaskan specimen. They range in size from 1 to 1/2 inch in diameter, are semi-translucent, and are colored a very dark wine-red. These are set into a classic matrix of dark gray Mica Schist, and given the weight of this specimen, probably have relatives hiding elsewhere in the matrix. There ARE benefits to spending one's childhood in Alaska!
no photo
alm-2 ($105.00)
Wrangell, Alaska, U.S.A.
ALMANDINE specimen alm-3
$ 95.00
Dims: 5" x 3-3/4" x 2-1/4"
Wt: 1 lb., 4 oz
Wrangell, Alaska, U.S.A.
A cluster composed of 3 intergrown Almandine garnets adorns this Austrian specimen. The cluster makes up most of the specimen's mass, being rather large (1.45 x 1.38 x 1.5 or 3.7 x 3.5 x 3.8 cm), with one garnet making up the bulk of the cluster. The garnets have a deep red color, a waxy luster and excellent dodecahedral form. Although they appear almost black under normal lighting, holding them up to a bright light will reveal a surprising amount of translucence, with a deep red color. The crystals are rife with internal fractures, which reflect the incoming light so that the viewer can see the color. It rests on a small amount of a nondescript gray schist host. I am impressed by this specimen!
no photo
alm-3 ($ 95.00)
Wrangell, Alaska, U.S.A.
ALMANDINE specimen alm-4
$ 25.00
Dims: 1.1" x 1.1" x 1.0"(2.8 x 2.8 x 2.5 cm)
Wt: 1.26 oz.(35.9 g)
Rhodesia
This specimen constitutes one of the most impressive garnets I have seen in a while. It has very good crystal form, and occurs in the 24-sided trapezohedral shape. While not being perfectly symmetrical, the crystal is complete, large, has very little damage, and has definite faces and edges. It is a dark red color, but most faces are covered with a brown crust that also reduces its luster to something between pearly and waxy. Internal fractures near the surface of uncovered faces reflect a wine-red color, indicating translucence, if not transparence. Apart from its good form and size, it comes from Rhodesia, a place from which I have not seen any mineral specimens before this!
no photo
alm-4 ($ 25.00)
Rhodesia
ALMANDINE specimen alm-7
$ 25.00
Dims: 2.4" x 1.8" x 1.1"(6.1 x 4.6 x 2.8 cm)
Wt: 2.18 oz.(62.2 g)
Wrangell, Alaska, U.S.A.
This little hand specimen consists of a small base of gray mica schist from which erupts a single Almandine garnet. It is a deep violet-red in color, has a vitreous luster, and is translucent, with small patches of transparence allowing one to see the many internal fractures within. The crystal measures approx. 0.8"(2.0 cm) in diameter and occurs in a variation of the dodecahedron in which all edges are truncated by thin secondary faces. It is an appropriate gift for a young rockhound or a collector that doesn't have much room for specimens.
no photo
alm-7 ($ 25.00)
Wrangell, Alaska, U.S.A.
ALMANDINE specimen alm-9
$ 35.00
Dims: 4.7" x 2.4" x 1.5" (11.9 x 6.1 x 3.8 cm)
Wt: 9.38 oz. (266.0 g)
Lake Martin, Alabama, U.S.A.
This small hand specimen consists of 8 visible Almandine garnet crystals that are partially embedded in the green mica schist host rock that is common for this locality. The crystals range in diameter from 0.2" (0.5 cm) to 0.6" (1.5 cm), and are generally in very good condition, though the smallest is broken and incomplete. They all have a rounded but discernable dodecahedral form and a very dull, waxy luster. One of the crystals is quite misshapen, but this appears to be due to the fact that it formed adjacent to another crystal, that prevented its completion. They have a deep wine-red coloration and show dim to moderate translucence, possibly due to their dull luster and partial visibility. I cannot be certain, but I think that there are other Almandine crystals in this matrix which are waiting to be exposed.
no photo
alm-9 ($ 35.00)
Lake Martin, Alabama, U.S.A.
ALMANDINE specimen alm-10
$ 50.00
Dims: 5.5" x 4.5" x 1.3" (14.0 x 11.4 x 3.3 cm)
Wt: 1 lb., 3.4 oz. (522 g)
Lake Martin, Alabama, U.S.A.
At least 20 Almandine garnets are visible in the green mica schist matrix of this large hand specimen. Though 4 of the crystals are damaged and one is badly broken, the rest are in excellent condition. Their dodecahedral form is somewhat rounded but still discernable, and their faces are generally striated and possess a rather dull pearly-to-waxy luster. All have the deep wine-red coloration that is standard for this type of garnet, and most are translucent. There are many more of these garnets buried in the matrix that can be easily exposed with a knife or other tools.
no photo
alm-10 ($ 50.00)
Lake Martin, Alabama, U.S.A.
ALMANDINE specimen alm-11
$ 55.00
Dims: 6.0 x 4.3 x 2.1" (15.2 x 10.9 x 5.3 cm)
Wt: 1 lb., 12.7 oz. (814.0 g)
Lake Martin, Alabama, U.S.A.
I have counted 24 Almandine garnets that are peeking out of the green mica schist matrix of this large hand specimen, and I know that there are many more trapped within its layers. They range in diameter from less than 0.1" (3 mm) up to at least 0.5" (1.3 cm), and are generally in good condition, though a few are obviously damaged. Their dodecahedral form is slightly rounded but still discernable, with moderately well-defined edges and striated but clean faces that possess a rather dull pearly luster. All have the deep wine-red coloration that is standard for Almandine, and though a few of the smaller crystals might be translucent individually, all are essentially opaque trapped in the schist matrix, which has a gray-green coloration and shows many of the characteristics of mica.
no photo
alm-11 ($ 55.00)
Lake Martin, Alabama, U.S.A.
ALMANDINE specimen alm-12
$ 60.00
Dims: 6.8 x 3.7 x 1.2" (17.3 x 9.4 x 3.0 cm)
Wt: 1 lb., 5.0 oz. (595 g)
Lake Martin, Alabama, U.S.A.
Twenty-five Almandine garnet crystals are visible and partly embedded in the green mica-schist host rock of this large hand specimen. These crystals range in diameter from 0.3" (8 mm) to 0.7" (1.8 cm) and are generally in moderately good condition, as several are obviously damaged, and a few are broken and incomplete. Those that are intact have moderately good dodecahedral form, with somewhat rounded but still definable edges and striated but clean faces that possess a rather dull, pearly-to-waxy luster. All have the classic deep wine-red coloration that are common for this type of garnet. Though most of the smaller crystals show reasonably good translucence, there is no visible transparence on any of them.
no photo
alm-12 ($ 60.00)
Lake Martin, Alabama, U.S.A.
ALMANDINE specimen alm-13
$ 130.00
Dims: 7.8 x 7.2 x 1.6" (19.8 x 18.3 x 4.1 cm)
Wt: 4 lbs., 5.3 oz. (1.964 kg)
Lake Martin, Alabama, U.S.A.
One of the larger specimens from this locality in our stock, this cabinet-size specimen consists of an amorphous chunk of green mica schist in which are embedded nearly 50 Almandine garnet crystals. They range in diameter from less than 0.1" (2 mm) to 0.6" (1.5 cm) and are generally in very good condition, though a few are obviously damaged. Though most of the smallest crystals are either slightly malformed or very rounded, the larger ones have very good dodecahedral form, with moderately well-defined edges and striated but clean faces that possess a rather dull, pearly-to-waxy luster. All have the standard deep wine-red coloration that is common for this mineral; most of the Almandines are only dimly translucent, if at all, but a few of the smallest ones are a bit clearer, and may show patches of transparence, though their rough surfaces spoil the view. It is highly probable that many more of these crystals are completely embedded in the schist host rock.
no photo
alm-13 ($130.00)
Lake Martin, Alabama, U.S.A.
ALMANDINE specimen alm-14
$ 85.00
Dims: 6.7 x 5.8 x 2.2" (17.0 x 14.7 x 5.6 cm)
Wt: 2 lbs., 14.3 oz. (1.312 kg)
Lake Martin, Alabama, U.S.A.
I have counted at least 28 different Almandine dodecahedrons on the green mica schist host rock of this hand specmien. The largest has a diameter of about 0.6" (1.5 cm) and all are in moderately good condition, as several show slight but noticeable damage and one crystal is broken and incomplete. Their form is somewhat rounded but still discernable in the larger crystals, but the smaller ones tend to be more rounded and warped, in some cases. They have the classic deep wine-red coloration and are likely only dimly translucent, though some of the small crystals might show more translucence and even patches of transparence. Their luster is pearly-to-waxy, and is actually duller than that of the surrounding matrix.
no photo
alm-14 ($ 85.00)
Lake Martin, Alabama, U.S.A.
ALMANDINE specimen alm-15
$ 25.00
Dims: 1.9 x 1.6 x 1.5" (4.8 x 4.1 x 3.9 cm)
Wt: 2.56 oz. (72.5 g)
Deer Park Mine, Spruce Pine, North Carolina, U.S.A.
At least 4 complete, intact Almandine crystals are embedded in the quartz host of this specimen. These crystals reach diameters of 0.4" (0.9 cm) and are in good condition, showing very little damage. All have the standard dodecahedral form, though 2 of the crystals are somewhat warped. Their color is a very deep red, but they are nearly opaque due to intense internal fracturing. A large amount of muscovite is also affixed to the quartz, as is a small amount of a feldspar.
no photo
alm-15 ($ 25.00)
Deer Park Mine, Spruce Pine, North Carolina, U.S.A.
ALMANDINE specimen alm-16
$ 60.00
Dims: 1.4 x 1.2 x 1.1" (3.5 x 3.0 x 2.8 cm)
Wt: 2.46 oz. (69.7 g)
Emerald Creek, Idaho, U.S.A.
This small hand specimen consists of a single Almandine crystal that was sold to us as a Star Garnet. I cannot tell whether or not it exhibits asterism, but it is one of the larger crystals in our present stock. It is in very good condition, showing two areas of light damage, and has excellent dodecahedral form, with secondary faces that truncate the main edges. One spot is warped, though- two depressions occur where the crystal formed adjacent to 2 other crystals. Its red color is so deep that the crystal is essentially opaque, and its luster is dull and greasy. There is no host rock present.
no photo
alm-16 ($ 60.00)
Emerald Creek, Idaho, U.S.A.
ALMANDINE specimen alm-17
$ 25.00
Dims: 4.1x3.0x1.3" (10.4x7.6x3.3cm)
Wt: 8.9oz (254.1g)
Lake Martin, Alabama, USA
The green mica schist of this colorful specimen hosts a half dozen almandine crystals (more may be buried in the mica). These crystals are small or at least poorly exposed, except for one fairly nice one. The alamandine is so dark as to appear almost black and opaque, but there are a few internal fractures close enough to the surface to reflect a light source with a pretty deep maroon-red color, and also reveal that this material is at least slightly translucent.
no photo
alm-17 ($ 25.00)
Lake Martin, Alabama, USA

 


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