Chlorite is a general name for several minerals that are difficult to distinguish by ordinary methods. These minerals are all apart of the Chlorite Group of minerals. The chlorites are often, but not always considered a subset of the larger silicate group, The clays.

The general formula for chlorite is (Fe, Mg, Al)6(Si, Al)4O10(OH)8. However there are several different minerals that are apart of the chlorite group of minerals. The above formula is only a generalization of the more common members of this group. In order to see a list of most of the chlorite group minerals with their respective formula, see the discussion of the Chlorite Group.

For practical reasons most of the chlorites will be considered here as a single mineral, chlorite. Chlorites are generally green and crystallize in the monoclinic symmetry system. They all have a basal cleavage due to their stacked structure. Chlorites typically form flaky microscopic crystals and it is this reason that they are sometimes included in the clay group of minerals. However chlorites also form large individual tabular to platy crystals that are unlike most of the other clay minerals.

Chlorites are most often known to mineral collectors as inclusions in or coatings on quartz, danburite, topaz, calcite and many other minerals. The inclusions are usually a very strong green color despite the small amount of material that actually constitutes the inclusion. These inclusions and coatings can be an enhancement but are more often a bane to what might have been a really valuable mineral specimen.

The chlorite inclusions in clear quartz are particularly interesting when they form as a coating on a crystal early in its development. Because if the crystal later grows larger, ie. out and around the chlorite coating, the effect will be to produce a phantomed crystal. A phantom is a crystal that appears to have a smaller crystal inside of it. Many times the interior "crystal" is indistinct or ghostly and thus the name phantom.

There are many minerals that make up the chlorites and thus many varieties. One variety is called kaemmererite and is a variety of the chlorite clinochlore. Sometimes kaemmererite is called chromian clinochlore because of the increase chromium content. It is the chromium that gives kaemmererite its bright lavender to deep crimson red color.


  • Color is usually green but can also be white, yellow, red, lavender and black.
  • Luster is vitreous, dull or pearly.
  • Transparency: Crystals are translucent transparent.
  • Crystal System is monoclinic; 2/m.
  • Crystal Habits: Rarely in large individual barrel or tabular crystals with an hexagonal outline. Usually found as alteration products of iron-magnesium minerals and as inclusions in other minerals. Aggregates can be scaly, compact, platy and as crusts.
  • Cleavage is perfect in one direction, basal; not seen in massive specimens.
  • Fracture is lamellar.
  • Hardness is 2 - 3
  • Specific Gravity is variable from 2.6 - 3.4 (average to slightly above average)
  • Streak is pal green to gray or brown.
  • Other Characteristics: Cleavage flakes are flexible but not elastic.
  • Associated Minerals include garnets, biotite, quartz, magnetite, talc, serpentine, danburite, topaz and calcite, among many others.
  • Notable Occurrences include Transvaal, South Africa; Zermatt, Switzerland; Guleman, Turkey; Lancaster Co., Pennsylvania, Brewster, New York; San Benito Co., California, USA and many other locallities world wide.
  • Best Field Indicators color, cleavage, associations and crystal habits.
CHLORITE specimens:
(hover for more info)
CHLORITE specimen cho-1
$ 37.50
Dims: 2" x 1-3/8" x 7/8"
Wt: 1.21 oz
Toruadri, Malenco Valley, Soudrio, Italy
Finally, some Chlorite that is large enough to really see! This specimen consists of dozens of small, bladed Chlorite crystals. They are transparent with a pale green color and have a pseudohexagonal form, and measure 1/8" in diameter, on average. There is a substantial amount of damage, but most of the crystals are in excellent condition. We've looked for a while to get some crystals of this mineral.
no photo
cho-1 ($ 37.50)
Toruadri, Malenco Valley, Soudrio, Italy
CHLORITE specimen cho-2
$ 30.00
Dims: 2.8 x 1.4 x 1.1" (7.1 x 3.6 x 2.8 cm)
Wt: 2.05 oz. (58.3 g)
Eden Mills, Lamoille County, Vermont, U.S.A.
One of the few specimens that I have seen from the northeastern U.S. state of Vermont, this specimen consists of many small Chlorite blades that fill a few seams in a dark green host rock. I cannot be sure, but I believe that they are made up of clinochlore, the most common member of the chlorite group. Their limited growth space and close proximity to each other keep them from exceeding 0.1" (3 mm) in any dimension of size, but also protect them. However, several of the most exposed blades are damaged to a degree. Their monoclinic prismatic form is also likely warped due to the growth restrictions, but its crystalline nature is definite. All have a very deep green coloration that approaches black, and show a dim translucence around their edges. The dark green host rock, apart from its color, looks a lot like quartzite.
no photo
cho-2 ($ 30.00)
Eden Mills, Lamoille County, Vermont, U.S.A.
CHLORITE specimen cho-3
$ 75.00
Dims:2.5x1.6x1.2" (6.4x4.1x3.0 cm)
Wt: 2.6oz. (75g)
Korshunovskoe, South Siberia, Russia
This specimen consists of radiating intergrown crystals of chlorite. These crystals are so intergrown that the top of the specimen where the crystals are weathered takes on a botryoidal appearance. On the edge of the specimen one can observe a "rind" of alteration material-again, the effects of weathering. The crystals also have a "greasy" feel to them. A most unusual (and oddly aesthetic) specimen.
no photo
cho-3 ($ 75.00)
Korshunovskoe, South Siberia, Russia
CHLORITE specimen cho-4
$ 69.00
Dims: 1.3x0.6x0.4" (3.4x1.4x1.0cm)
Wt: 0.12 oz. (3.5g)
Itremo, Madagascar
This is a pair of phantom quartz crystals, formed when the growing quartz crystals grew a layer of chlorite crystals then continued to grow to their present size. Such phantoms are almost common. What makes this one special is that the chlorite is an especially pure green, and that there is a spray of chlorite crystals growing from the tips of each phantom. These look very much like tiny blades of moss growing inside the quartz crystals. A loupe with 15x or better magnification may be needed to appreciate this specimen, as a lower power may not resolve the individual chlorite crystals.
no photo
cho-4 ($ 69.00)
Itremo, Madagascar
CHLORITE specimen cho-5
$ 39.00
Dims: 2.89x2.53x2.05" (7.35x6.42x5.21cm)
Wt: 4.46oz (126.3g)
Sinia Rechka, Vladivostok, Russia
This is a specimen of "prase", an obsolete term for the green translucent variety of crystalline quartz. Chrysoprase is a (cryptocrystalline) green agate, and this specimen displays large well-formed crystals. The green color is due to chlorite inclusions, and a high-power loupe reveals the presence of chlorite crystals in some of the clearer quartz crystals, although in general the chlorite is evenly distributed and the quartz appears uniformly green. This specimen also contains a brown crust, which a loupe reveals as hundreds of andradite garnet crystals. The specimen came from the Sinia river valley, 300km from Vladivostok.
no photo
cho-5 ($ 39.00)
Sinia Rechka, Vladivostok, Russia


Copyright ©1995-2023 by Amethyst Galleries, Inc.