Lawsonite
Lawsonite is a hydrous calcium aluminium sorosilicate mineral with formula CaAl2Si2O7(OH)2·H2O. Lawsonite crystallizes in the orthorhombic system in prismatic, often tabular crystals. Crystal twinning is common. It forms transparent to translucent colorless, white, and bluish to pinkish grey glassy to greasy crystals. Refractive indices are nα=1.665, nβ=1.672 - 1.676, and nγ=1.684 - 1.686. It is typically almost colorless in thin section, but some lawsonite is pleochroic from colorless to pale yellow to pale blue, depending on orientation. The mineral has a Mohs hardness of 8 and a specific gravity of 3.09. It has perfect cleavage in two directions and a brittle fracture.

Lawsonite is a metamorphic mineral typical of the blueschist facies. It also occurs as a secondary mineral in altered gabbro and diorite. Associate minerals include epidote, titanite, glaucophane, garnet and quartz. It is an uncommon constituent of eclogite.

It was first described in 1895 for occurrences in the Tiburon peninsula, Marin County, California. It was named for geologist Andrew Lawson (1861–1952) of the University of California by two of Lawson's graduate students, Charles Palache and Frederick Leslie Ransome.
None
sorosilicate
UNK
Q648961
orthorhombic
Concept
Q109856
Crystal twinning
UNK
Q487623
translucent
Concept
Q174102
Refractive indices
Concept
Q112895
pleochroic
Concept
Q41472
Mohs hardness
Concept
Q11027905
specific gravity
Concept
Q380971
metamorphic
Concept
Q1048428
blueschist facies
Concept
Q46947
gabbro
Concept
Q187408
diorite
Concept
Q272844
epidote
Concept
Q377280
titanite
Concept
Q413272
glaucophane
Concept
Q105368
garnet
Concept
Q43010
quartz
Concept
Q729546
eclogite
Concept
Q108117
Marin County, California
LOC
Q520549
geologist
Concept
Q504233
Andrew Lawson
PER
Q184478
University of California
ORG
Q1065718
Charles Palache
PER
Q5498268
Frederick Leslie Ransome
PER
Q424354
Lawsonite
Concept
Q424354
Lawsonite
Concept
Q424354
Lawsonite
Concept
1895-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
1895
DATE
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+7^^http://www.w3.org/2001/XMLSchema#decimal
7
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
+1.665^^http://www.w3.org/2001/XMLSchema#decimal
1.665
NUMBER
+1.672^^http://www.w3.org/2001/XMLSchema#decimal
1.672
NUMBER
+1.676^^http://www.w3.org/2001/XMLSchema#decimal
1.676
NUMBER
+1.684^^http://www.w3.org/2001/XMLSchema#decimal
1.684
NUMBER
+1.686^^http://www.w3.org/2001/XMLSchema#decimal
1.686
NUMBER
+8^^http://www.w3.org/2001/XMLSchema#decimal
8
NUMBER
+3.09^^http://www.w3.org/2001/XMLSchema#decimal
3.09
NUMBER
+1861^^http://www.w3.org/2001/XMLSchema#decimal
1861
NUMBER
+1952^^http://www.w3.org/2001/XMLSchema#decimal
1952
NUMBER
crystal system
named after
occupation
occupation