It crystallizes in the orthorhombic system and forms translucent bright blue acicular crystal clusters or Refractive indices are n? = 1.588 n? = 1.617 n? = 1.655.
22.
Euchroite "'is a hydrated copper arsenate hydroxide mineral with formula : Cu 2 AsO 4 OH?H 2 O . It is a vitreous green to emerald green mineral crystallizing in the orthorhombic system.
23.
The orthorhombic system is described as having three crystallographic axes of unequal lengths, normally referred to as c ( the longest axes ), b ( the second longest axes ), and a ( the smallest axes ).
24.
"' Struvite "'( magnesium ammonium phosphate ) is a phosphate mineral with formula : NH 4 MgPO 4 ?H 2 O . Struvite crystallizes in the orthorhombic system as white to yellowish or brownish-white pyramidal crystals or in platey mica-like forms.
25.
In the orthorhombic system there is a second choice of crystal axes that results in a unit cell with the shape of a right rhombic prism, although this axis setting is very rarely used; this is because the rectangular two-dimensional base layers can also be described with rhombic axes.
26.
(NH 4 ) Zr ( NO 3 ) 5 . HNO 3 crystallizes in the orthorhombic system, space group Pna2 1 with unit cell dimensions a = 14.852 ?b = 7.222 ?c = 13.177 ?? = 90?volume 1413.6 ?3 with 4 formulae per cell, density = 2.267.
27.
"' Jonesite "'is a mineral with the chemical formula Ba 4 ( K, Na ) 2 [ Ti 4 Al 2 Si 10 O 36 ] * 6H 2 O . This mineral is named after Francis Tucker Jones ( 1905 1993 ), who discovered the mineral while working as a Research Chemical Microscopist at Berkeley in CA . Jonesite has diffraction symmetry of mmm, which implies an orthorhombic system with all three axes perpendicular to each other and the angles between each axis equal to 90 degrees.
