THE MINERAL MESOLITE

  • Chemistry: Na2Ca2Al6Si9O30 - 8H2O, Hydrated sodium calcium aluminum silicate
  • Class: Silicates
  • Subclass: Tektosilicates
  • Group: Zeolites
  • Uses: mineral specimen and chemical filter
  • Specimens

Mesolite is a popular zeolite mineral for mineral collectors and zeolite collectors in particular. Its radiating sprays of ice-clear acicular crystals are a hallmark of this mineral. Often associated with minerals such as the green or clear apophyllite, the pink and pearly heulandite and the sparkling tiny crystals of quartz, mesolite is a wonderful addition in both style and rarity to these great mineral assemblages. Mesolite is often found in geodes containing other zeolites.

Mesolite's structure has a typical zeolite openness about it that allows large ions and molecules to reside and actually move around inside the overall framework. The structure contains open channels that allow water and large ions to travel into and out of the crystal structure. The size of these channels controls the size of the molecules or ions and therefore a zeolite like mesolite can act as a chemical sieve. Mesolite's structure contains chains of silicate tetrahedrons aligned in one direction and this produces the needle-like crystals and the cleavage results from the weaker bonds between the chains.

Mesolite, a sodium calcium zeolite, is intermediate between natrolite, a sodium zeolite, and scolecite, a calcium zeolite. They are closely related and sometimes found together. The presence of calcium in two of the minerals slightly alters the structure from that of natrolite from an orthorhombic symmetry to a monoclinic symmetry. Although twinning of scolecite and mesolite often make them look orthorhombic The three minerals are referred to as "chain" or "needle" zeolites. They are similar and hard to distinguish when in clusters with radiating, acicular habits. Natrolite forms thinner crystals with pyramidal terminations, and mesolite's fiber-like crystals are usually the thinnest crystals of the three minerals. Scolecite's larger crystals tend to be more robust and durable. These characteristics are only generalities and can not be used as dependable identifying traits. Absolute identification can not be made by ordinary means.

PHYSICAL CHARACTERISTICS:

  • Color is clear or white.
  • Luster is vitreous.
  • Transparency: crystals are transparent to translucent.
  • Crystal System is monoclinic; 2/m
  • Crystal Habits include sprays of needle thin acicular crystals with a slanted domal termination. Also nodules, fibrous and earthy masses.
  • Cleavage is perfect in two directions, prismatic. Cleavage is rarely seen due to small crystal size.
  • Fracture is conchoidal to uneven.
  • Hardness is 5 - 5.5.
  • Specific Gravity is approximately 2.2 - 2.4 (very light)
  • Streak is white.
  • Other Characteristics: Masses can have a chatoyant (cat's eye) effect.
  • Associated Minerals are quartz, apophyllite, datolite, heulandite, stilbite and other zeolites.
  • Notable Occurrences include Poona, India; Giants Causeway, Ireland; Skye, Scotland; Colorado, New Jersey and Oregon, USA and Berufjord, Iceland.
  • Best Field Indicators are crystal habit, density and associations.
MESOLITE specimens:
(hover for more info)
MESOLITE specimen mes-1
$ 80.00
Dims: 3-3/4" x 1-3/4" x 1-1/4"
Wt: 1.83 oz
Poona, India
There is basically no matrix on this specimen; only a tiny crust remains at the base of the splendid spray of Mesolite crystals that constitutes this specimen. The individual crystals are transparent and colorless, have almost no damage, and are generally 3/16" wide or less. I think that this is a splendid specimen!
no photo
mes-1 ($ 80.00)
Poona, India
MESOLITE specimen mes-4
$ 75.00
Dims: 3.4" x 2.0" x 1.7" (8.6 x 5.1 x 4.3 cm)
Wt: 2.52 oz. (71.4 g)
Poona, India
A radiating cluster of long, thin Mesolite crystals constitutes this Indian specimen. Their maximum length is just under 3.0" (7.5 cm), and they do not exceed 0.2" (0.5 cm) in either of their other dimensions. They occur in long, thin, needle-like crystals that have good form. All are colorless, though the material near their point of radiation is white with a faint tinge of pink. They are transparent and quite clear, and though many of them are damaged and broken, most are in excellent condition, with clean faces and edges that show a vitreous luster. It is a delicate specimen that should be handled as little as possible, and with care.
no photo
mes-4 ($ 75.00)
Poona, India
MESOLITE specimen mes-6
$ 150.00
Dims: 6.3" x 5.8" x 3.5" (16.0 x 14.7 x 8.9 cm)
Wt: 4.75 lbs. (2.1 kg)
Poona, India
One of the more impressive Indian zeolite specimens in our stock, this piece consists of a vug that passes completely through the basalt host rock. The vug is lined with a variety of silicate mineral crystals, including tiny, transparent quartzes, "wheat-sheaf" aggregates of stilbite, what appears to be an almost cubic calcite, and even hundreds of tiny laumontites. Amidst all of this confusion is a radiating cluster of thick, needle-like Mesolite crystals. They all radiate from a single point, which is visible near the smaller opening in the vug and reach a maximum length of about 2.0" (5.1 cm), but do not exceed 3 mm in either width or depth. They have a milky-white color and a pearly-to-vitreous luster, and are translucent. There is very little damage to the cluster- the crystals that show damage are those which are exposed at the smaller opening to the hollow, but this area would be construed as the "bottom" of the specimen, and the damage is not visible when one looks into the hollow through the larger opening. It is quite entertaining to study, and will take a while to do so.
no photo
mes-6 ($150.00)
Poona, India
MESOLITE specimen mes-7
$ 60.00
Dims: 2.9 x 1.1 x 0.6" (7.3 x 2.8 x 1.5 cm)
Wt: 14.0 g
Poona, Maharashtra State, India
This small hand specimen consists of a single, narrow spray of radiating Mesolite needles. These needles achieve lengths as great as that of the entire specimen, but do not exceed 0.1" (3 mm) in either of the other dimensions. They are generally in good condition, as there are several breakage areas where crystals broke off near their point of intergrowth. All have excellent monoclinic prismatic form, with well-defined edges and striated but clean faces that possess a bright pearly luster. Individually, each crystal is colorless, transparent, and quite clear, but take on a milky-white coloration and a dim translucence where they start to intergrow at the base of the specimen. There is no host rock present, and care must be taken in handling this delicate piece.
no photo
mes-7 ($ 60.00)
Poona, Maharashtra State, India
MESOLITE specimen mes-8
$ 150.00
Dims: 3.7 x 1.6 x 1.5" (9.4 x 4.1 x 3.8 cm)
Wt: 1.89 oz. (53.6 g)
Poona, Maharashtra State, India
A single spray of radiating Mesolite crystals comprises this hand specimen. The spray is in moderately good condition, as many of the long, thin needles are broken. They reach lengths of up to 3.5" (8.9 cm) and show excellent monoclinic form, with well-defined edges and striated but clean faces that possess the standard pearly luster. Like most Mesolite crystals, these are colorless, transparent, and generally quite clear, though a few do contain visible veil-like inclusions. All take on a milky-white coloration and become merely translucent where they intergrow near their base. There is no host rock present, but the spray is attached at its base to a single, cube-shaped apophyllite.
no photo
mes-8 ($150.00)
Poona, Maharashtra State, India
MESOLITE specimen mes-9
$ 350.00
Dims: 3.7 x 3.0 x 1.9" (9.4 x 7.6 x 4.8 cm)
Wt: 6.15 oz. (174.5 g)
Poona, Maharashtra State, India
One of the largest such specimens that we have yet had, this piece consists of a single large spray of radiating Mesolite needles. These crystals acheive lengths of up to 3.9" (9.9 cm) and are generally in moderately good condition, as many are damaged or broken. Their monoclinic form is excellent, with well-defined edges and striated, clean faces that possess a bright pearly luster. All are nearly colorless, though a faint pinkish discoloration is visible near the base of the spray. They are transparent and mostly clear near their terminations, but cloud to a milky-white translucence towards their base. A substantial portion of the sidelong surface of the cluster is coated with a thin calcite crust, on which are attached a few small pieces of basalt host rock. There is also a cluster of warped and partly intergrown stilbites attached to the outer surface of the spray, with a few Mesolites growing off of them in random directions. They have the standard form (though warped), color and luster of stilbite.
no photo
mes-9 ($350.00)
Poona, Maharashtra State, India
MESOLITE specimen mes-10
$ 78.00
Dims: 2.3 x 1.5 x 1.0" (5.8 x 3.8 x 2.5 cm)
Wt: 2.77 oz. (78.7 g) w/ specimen box
Douglas County, Oregon, U.S.A.
This delicate specimen consists of a spray of scores of very fine Mesolite needles, along with a group of "loose", unclustered needles. Those needles in the spray are considerably longer than the "loose" ones, achieving lengths of nearly 1.7" (4.3 cm). The loose crystals are much shorter, and do not exceed 0.7" (1.8 cm)- none are thicker than an average human hair, as far as I can tell, making it impossible to study their monoclinic form, which is likely very good. All have the colorless/white coloration and pearly luster that is standard for the species, and the very base of the spray shows a definite gray and very subtle pink coloration. They are accompanied by a single, colorless calcite crystal (the "loose" Mesolites intersect it) and a small amount of Thomsonite, which I believe has formed a crust beneath the Mesolite spray. There is only little evidence of the basalt host rock, and the specimen has been glued into a square plastic speciemen box.
no photo
mes-10 ($ 78.00)
Douglas County, Oregon, U.S.A.
MESOLITE specimen mes-11
$ 45.00
Dims: 2.2 x 1.8 x 1.2" (5.6 x 4.6 x 3.0 cm)
Wt: 22.9 g
Poona, Maharashtra State, India
This rather simple thumbnail specimen consists almost entirely of a radiating spray of Mesolite needles. These needles are generally in very good condition, showing only slight to moderate breakage, and reach lengths of 1.8" (4.6 cm). They show excellent monoclinic form, with well-defined edges and clean faces that possess the standard pearly luster. Each crystal is transparent and very clear at its termination, but tends to dim to translucence and take on a white color towards its base. There is only a very small piece of quartz- or caclite-encrusted basalt attached to the spray.
no photo
mes-11 ($ 45.00)
Poona, Maharashtra State, India
MESOLITE specimen mes-12
$ 45.00
Dims: 3.1 x 1.6 x 1.2" (7.9 x 4.1 x 3.0 cm)
Wt: 1.35 oz. (38.5 g)
Poona, Maharashtra State, India
This small hand specimen consists of two intersecting sprays of Mesolite needles, the larger of which is partly intergrown with a cluster of apophyllites. The smaller cluster does not exceed 0.5" (1.3 cm) in length, and is made up of only a few crystals. However, the larger cluster contains dozens of crystals, one of which exceeds 3" (7.6 cm). The cluster is in moderately good condition, as many crystals are broken, but those that are intact are in excellent shape. Their monoclinic form is excellent and is topped by shallow domed terminations. All have well-defined edges and striated but clean faces that possess a pearly luster. They are colorless, transparent and quite clear at their terminations, though they tend to cloud to a translucent white at their bases. The accompanying apophyllites are both broken and badly warped, so that their tetragonal form is almost undefinable. There is no base rock present.
no photo
mes-12 ($ 45.00)
Poona, Maharashtra State, India
MESOLITE specimen mes-13
$ 150.00
Dims: 5.0 x 4.7 x 4.0" (12.7 x 11.9 x 10.2 cm)
Wt: 3 lbs., 12.0 oz. (1.700 kg)
Poona, Maharashtra State, India
A single Mesolite spray rests in a vug inside the basalt host rock of this large hand specimen. The spray has general dimensions of 1.2 x 1.1 x 0.9" (3.0 x 2.8 x 2.3 cm), and contains crystals that reach 1.1" (2.8 cm) in length. Being protected in their hollow, the crystals all appear to be in pristine condition. They have excellent monoclinic prismatic form and have a bright pearly luster. All are colorless, transparent, and are quite clear, though the cluster as a unit has a milky-white coloration and is only translucent. The Mesolite spray is accompanied by several small calcite crystals, some of which appear to be very warped. The interior surface of the vug is lined with massive to crystalline quartz, some of which has a stalactitic form.
no photo
mes-13 ($150.00)
Poona, Maharashtra State, India
MESOLITE specimen mes-14
$ 120.00
Dims: 5.0 x 4.2 x 2.7" (12.7 x 10.7 x 6.9 cm)
Wt: 3 lbs., 7.5 oz. (1.574 kg)
Bombay, India
Two partly-intersecting Mesolite sprays rest in a vug in the basalt host of this specimen. These sprays are nearly identical in size, containing crystals that reach nearly 1.1" (2.8 cm) in length. The crystals are generally in excellent condition- only a few are visibly damaged- and have excellent monoclinic needle-like form. All are colorless, transparent and very clear, and have the standard bright pearly luster. They are accompanied in the vug by several stubby, pseudocubic apophyllites that have good form and are also colorless and transparent.. The vug itself appears to be lined with a thin quartz crust.
no photo
mes-14 ($120.00)
Bombay, India
MESOLITE specimen mes-15
$ 90.00
Dims: 4.0 x 2.2 x 1.9" (10.2 x 5.6 x 4.8 cm)
Wt: 5.32 oz. (150.9 g)
Poona, India
Three intersecting Mesolite sprays make up this hand specimen. Each is made up of dozens of needle-like Mesolite crystals that reach lengths of 3.8" (9.7 cm). These crystals are in moderately good condition, as there are a few areas of visible damage. Many are warped, but many more have excellent monoclinic form, with well-defined edges, clean faces and nearly basal domed terminations. All are colorless, transparent and moderately clear, and have a bright pearly luster. The clusters, however, show a generally milky white coloration with a faint hint of pink. A few broken apophyllites and a small amount of damaged geen heulandite is present, but there is no base rock.
no photo
mes-15 ($ 90.00)
Poona, India
MESOLITE specimen mes-16
$ 65.00
Dims: 3.10x2.18x1.42" (7.88x5.53x3.61cm)
Wt: 2.93oz (82.9g)
Pune, India
This mesolite puffball is quite dense. The crystals are generally very thin (0.2mm), and average about 2½ cm long. They are clear and colorless, and have excellent form. The puffball is acompanied by a single green apophyllite crystal, a cube with truncated points roughly 1cm on a side. This specimen is very fragile, in that the needles easily break off, but there are so many that the damage is not noticeable.
no photo
mes-16 ($ 65.00)
Pune, India
MESOLITE specimen mes-17
$ 84.00
Dims: 3.03x2.50x2.04" (7.70x6.35x5.19cm)
Pune, India
This is a beautiful spray of mesolite crystals. They originate on a porous host mixture of crystals, some of which look like tiny quartz crystals, some of look like opaque blades of albite, and some of which are tiny random needles. Together, these hold the mesolite rather loosely, resulting in a rather fragile specimen (the needles are easily pulled out). Luckily there are thousands of mesolite crystals, so losing a dozen here or there does not noticably detract from the specimen. The individual mesolite crystals are very well-formed, with square cross sections and shallow pyramidal terminations. They are also transparent and colorless when viewed from the side, but they have a white dusting that tends to make them look white when viewed at an angle. The terminations do not have this coating, which gives an interesting effect: the individual crystals look dark at their tips, which is actually due to seeing into the depths of the clear crystals, while the outside faces have that whitish appearance.
no photo
mes-17 ($ 84.00)
Pune, India
MESOLITE specimen mes-18
$ 68.00
Dims: 1.44x2.45x2.00" (3.66x6.22x5.09cm)
Wt: 0.98oz (27.8g)
Pune, India
This fragile specimen has two intersecting clusters of radial mesolite crystals, although one cluster is by far the largest. The shape indicates that the largest is actually two clusters. The individual crystals are well-formed, and while they appear white, they are individually transparent and the crystal tips appear dark due to seeing down into the crystal. The specimen is extremely fragile - any handling results in the loss of some acicular crystals, but there are thousands of them, so the loss of a few is not noticable.
no photo
mes-18 ($ 68.00)
Pune, India

 


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