• Chemistry: Ca2 Si3 O7(OH)2 -H2 O, Hydrated calcium silicate hydroxide.
  • Class: Silicates
  • Subclass: Phyllosilicates
  • Uses: mineral specimen
  • Specimens

Gyrolite often forms nodular aggregates. These aggregates can appear glassy, dull or even fiberous. Unlike other similar looking minerals (such as prehnite or smithsonite), gyrolite usually forms individual nodules as opposed to botryoidal or crustal growths. The aggregate nodules can often accompany many fine and rare minerals such as apophyllite, okenite and many of the zeolites. Much gyrolite forms inside of volcanic bubbles called vesicles and can only add another element to the surreal "landscape" inside.


  • Color is white or colorless. Also green or brown.
  • Luster is vitreous to dull.
  • Transparency crystals are transparent to translucent.
  • Crystal System is triclinic; bar 1
  • Crystal Habits include the nodules described above. Nodules or concretions are lamellar to fiberous.
  • Cleavage is perfect in one direction.
  • Fracture is uneven.
  • Hardness is 3 - 4.
  • Specific Gravity is approximately 2.3+ (below average)
  • Streak is white.
  • Other Characteristics: lacks the luster of smithsonite and prehnite is usually greener in color.
  • Associated Minerals are okenite, apophyllite, quartz, laumontite and other zeolites.
  • Notable Occurrences include Poona, India; California and Northern Ireland.
  • Best Field Indicators are crystal habit, luster and associations.
GYROLITE specimens:
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GYROLITE specimen gyr-1
$ 90.00
Dims: 6.0" x 2.2" x 2.0"(15.2 x 5.6 x 5.1 cm)
Wt: 6.38 oz.(181.1 g)
Bombay, India
This is a magnificent specimen- I've never seen anything like it! Hundreds of dull green Gyrolite orbs are scattered on this piece. They have a dull waxy luster and range in size from less than 1 mm to 0.3(8 mm) in diameter. They are accompanied by a few dozen prehnite globules that are similar in size and luster but are harder to detect due to their pale green-white coloration. These orbs rest on a bed of very fine quartz crystals that are colorless and have good form and transparence, but are difficult to see because of their tiny size (2 mm max. length), and the fact that they grow out of white pipe-straw calcite that is in the form of long, thin, strawlike stalactites and have a triangular cross-section that is easily seen on each end of the piece. I dearly love this specimen, and I was disappointed that there wasn't another one that I could buy for myself.
no photo
gyr-1 ($ 90.00)
Bombay, India
GYROLITE specimen gyr-2
$ 40.00
Dims: 2.7" x 1.9" x 1.5"(6.9 x 4.8 x 3.8 cm)
Wt: 3.17 oz.(90.1 g)
Bombay, India
This simple specimen consists of two orbicular globules of Gyrolite in a hollow in a basalt base rock. The orbs have a white color, dull luster, and are translucent. One measures 0.8"(2.0 cm) in diameter and a smaller one adjacent to it has a diameter of 0.3"(8 mm). The larger one has a very regular shape that resembles an almost perfect hemi-sphere, whereas the smaller one is less complete. A small impact scar on the larger orb makes up the extent of the visible damage. I don't think I have seen a better example of Gyrolite than this specimen.
no photo
gyr-2 ($ 40.00)
Bombay, India
GYROLITE specimen gyr-3
$ 32.00
Dims: 2.7" x 1.9" x 1.5"(6.9 x 4.8 x 3.8 cm)
Wt: 3.17 oz.(90.1 g)
Bombay, India
Hundreds of small green Gyrolite aggregates that are mostly intergrown rest on the prehnite host rock of this specimen. They have a dark gray-green color and a dull, silky luster, and are dimly translucent. All are spherical in shape and striations on them are easy to see, denoting the crystals that make up each globule. A few are broken and a few are slightly damaged, but they make up less than 1% of the total number of these little orbs. They rest on a dull white layer of prehnite that is translucent and has a dull luster. The prehnite rests on an all-but-invisible layer of tiny, clear quartz crystals. There are a few bits of what appears to be okenite among the Gyrolites, too. I really liked examining this specimen because of the variety of materials that constitutes it.
no photo
gyr-3 ($ 32.00)
Bombay, India
GYROLITE specimen gyr-4
$ 108.00
Dims: 3.9 x 3.9 x 1.9" (9.9 x 9.9 x 4.8 cm)
Wt: 13.6 oz. (386.0 g)
Poona, India
At least 25 round Gyrolite clusters rest on the basalt base rock of this hand specimen. These nodules are generally in excellent condtion, showing no human-induced damage, and range in diameter from 0.1 - 0.9" (0.3 - 2.3 cm). All are made up of scores of tightly compact, rounded blades, of which only the edges are visible. The clusters generally have good form and possess a creamy-white coloration and a dull luster. They are accompanied by several pseudocubic calcites that are also in excellent condition and have dimensions similar to those of the Gyrolites. Their form is very good, and they are generally colorless, transparent, and quite clear, though several of them contain dark brown inclusions. They rest on a thin druse of tiny quartz crystals that coat the dark green igneous base.
no photo
gyr-4 ($108.00)
Poona, India
GYROLITE specimen gyr-5
$ 96.00
Dims: 3.7 x 2.7 x 2.2" (9.4 x 6.9 x 5.6 cm)
Wt: 10.8 oz. (305 g)
Poona, Maharashtra State, India
At least 10 round Gyrolite nodules rest on the concave surface of this hand specinen. All but two of these nodules are intergrown into clusters, and they range in diameter from 0.1" (3 mm) to 0.6" (1.5 cm). Two of the clusters which rest on the edge of the surface are damaged and not quite complete, but the rest are in excellent condition. Their round, nodular habit is a common aspect of their triclinic form, and all have a dull green color and a dull, waxy luster. Most are dimly translucent. They are accompanied by a large cluster of calcite prisms that seem to erupt from one of the Gyrolite clusters, and the hollow in the basalt host rock in which they rest is lined with countless tiny quartz crystals.
no photo
gyr-5 ($ 96.00)
Poona, Maharashtra State, India
GYROLITE specimen gyr-6
$ 28.00
Dims: 3.5 x 2.6 x 2.0" (8.9 x 6.7 x 5.2 cm)
Wt: 9.0 oz. (254 g)
Bombay, India
This cabinet specimen shows a variety of zeolite minerals that can be found at the famous localities in India. The most notable, however, are several large Gyrolite nodules that rest on the basalt base. These nodules reach nearly 0.4" (1 cm) in diameter and are generally in excellent condition. No actual crystals are visible, as all have aggregated into the round nodules. Their surfaces, however, show evidence of the Gyrolite's triclinic form. All have a dull, olive-green color and a dull luster, and are dimly translucent at best. They are accompanied by many smaller, milky-white prehnite nodules, a few incomplete, decaying laumontite crystals, a single okenite spray, and countless tiny quartz crystals that rest on the white chalcedony crust which covers the basalt base.
no photo
gyr-6 ($ 28.00)
Bombay, India
GYROLITE specimen gyr-7
$ 60.00
Dims: 2.10x1.46x0.90" (5.33x3.70x2.30cm)
Wt: 1.71oz (48.3g)
Malad Quarry, Mumbai (Bombay), Maharashtra, India
This specimen displays one large and several small gyrolyte clusters on a matrix composed largely of colorless transparent crystals. The gyrolite is subtly green, and a loupe reveals that the spherical clusters are composed of rounded books of thin translucent crystals. I believe that the matrix mineral is apophyllite, as the crystals are complex, even rounded, but the common form is cubic, and the crystals have faint striations.
no photo
gyr-7 ($ 60.00)
Malad Quarry, Mumbai (Bombay), Maharashtra, India


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