Lizardite
Current inventory:  0 gems
 

  
Lizardite was named in 1955 by Eric James William Whittaker and Jack Zussman after the locality of discovery; Lizard Peninsula, Cornwall, England.

Discovered in 1956; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Mg₃Si₂O₅(OH)₄

Magnesium Silicate Hydroxide

Molecular Weight:

277.11 gm

Composition:

Magnesium

26.31 %

Mg

43.63 %

MgO

Silicon

20.27 %

Si

43.36 %

SiO₂

Hydrogen

1.45 %

H

13.00 %

H₂O

Oxygen

51.96 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/H.27-20

Nickel-Strunz 10th Ed. ID:

9.ED.15

9 : SILICATES (Germanates)
E : Phyllosilicates
D : Phyllosilicates with kaolinite layers composed of tetrahedral and octahedral nets

Related to:

Serpentine Group (subgroup of the Kaolinite-Serpentine Group). Polymorphous with Antigorite and Chrysotile. Forms a series with Népouite. 

Members of Group:

Serpentine Group: Antigorite, Chrysotile, Lizardite.
Kaolinite-Serpentine Group: Amesite, Antigorite, Baumite, Berthierine, Brindleyite, Caryopilite, Chrysotile, Clinochrysotile, Cronstedtite, Dickite, Fraipontite, Greenalite, Halloysite, Kaolinite, Kellyite, Lizardite, Manandonite, Nacrite, Népouite, Odinite, Orthochrysotile, Parachrysotile, Pecoraite, Webskyite

Varieties:

Scyelite

Synonyms:

Al-lizardite, Baumite, Nickeloan Lizardite

Crystal Data

Crystallography:

Triclinic - Pinacoidal

Crystal Habit:

Crystals rare, to 2 mm, as trigonal plates to truncated trigonal pyramids. Commonly as extremely fine-grained scales and massive aggregates. 

Twinning:

None

Physical Properties

Cleavage:

Perfect on {0001}

Fracture:

n/a

Tenacity:

Crystals are easily bent

Moh's Hardness:

2.50

Density:

2.55 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Green, light yellow to white; colorless to pale green in thin section

Transparency:

Translucent

Luster:

Waxy

Refractive Index:

1.538 - 1.568  Uniaxial ( - ) to slightly Biaxial ( - )

Birefringence:

0.012

Dispersion:

Weak to distinct

Pleochroism:

n/a

Occurances

Geological Setting:

Typically a product of retrograde metamorphism, replacing olivine, orthopyroxene, or other minerals in ultramafic igneous rocks.

Common Associations:

Chrysotile, Brucite, Magnetite

Common Impurities:

n/a

Type Locality:

Eastern Cliff, Kennack Cove (Kennack Sands), Kennack, Grade-Ruan, Lizard Peninsula, Cornwall, England, UK

Year Discovered:

1956

View mineral photos:

Lizardite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Lizardite is a member of the Serpentine Group of minerals that also includes Antigorite and Chrysotile. These three minerals are polymorphous, meaning they have essentially the same chemistry but different structures. Antigorite is a fairly common member of the group, but Lizardite is the most abundant Serpentine. The Serpentine Group is a subgroup of the Kaolinite-Serpentine Group. At a Moh's hardness of only 2.5 it is very soft, but its bright, apple green colors make for beautiful cabochons for collectors.

Lizardite distribution: Probably the most common serpentine mineral. A few prominent localities for well-studied material include: at Kennack Cove, The Lizard, Cornwall, England. On Unst, Shetland Islands, Scotland. From near Val Sissone, Lombardy, and Val Trebbia, Piacenza, Italy. In Japan, from Maruo Odori and Kodo, Yamaguchi Prefecture, and at Hamao, Fukuoka Prefecture. At Woodsreef, New South Wales, Australia. From the Jeffrey mine, Asbestos, Quebec, and the Cassiar mine, British Columbia, Canada. In the USA, at the Stillwater complex, Montana.
 

  
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