Suanite

Suanite
General
Category	Borate mineral
Formula (repeating unit)	Mg2B2O5
Strunz classification	6.BA.05
Crystal symmetry	Monoclinic - prismatic H-M symbol (2/m) Space group: P 21/a
Unit cell	a = 12.31 Å, b = 3.12 Å c = 9.2 Å; β = 104.33°
Identification
Color	White to pale gray
Crystal habit	Clusters of prismatic to fibrous crystals
Crystal system	Monoclinic
Cleavage	Perfect parallel to {010}
Mohs scale hardness	5.5
Luster	Silky to pearly
Streak	White
Diaphaneity	Translucent
Specific gravity	2.91
Optical properties	Biaxial (–)
Refractive index	nα = 1.596 nβ = 1.639 nγ = 1.670
Birefringence	δ = 0.074
2V angle	70°
References

Suanite is a magnesium borate mineral with formula Mg₂B₂O₅.

It was first described in 1953 by Japanese scientist Takeo Watanabe from the University of Tokyo. His first contact with the mineral was during analysis of gold- and copper- bearing skarn minerals from the Hol Kol mine, located in North Korea obtained in 1939. Due to the small sample size available to him, he was only able to determine the unknown substance's optical properties under a microscope. Watanabe was able to return to the site in 1943 and obtain further samples that permitted him to perform chemical analysis on the material.