We'll start by briefly defining the group our gem belongs to,known as NESOSILICATES.
Nesosilicates are also referred to as Orthosilicate or Island silicates. They are the isolated group. They are a group of minerals that contain discreet SiO4 (tetrahedral). Examples are the Olivine group,the Garnet group,Sphene,Zircon.
We'll be looking at just the Olivine group this time.
OLIVINE GROUP
Physical properties
•Crystal structure if Olivine is Othorhombic
•Form and Habit: stubby chrismatic crystals and compact grains
•Colour: Shades of green,pale green,olive gree ,white or yellow in fosterite and black or brown in fayalite
•Cleavage: Poor
•Fracture: Cracks are usually present
•Transparency: Transparent to translucent
•Hardness: 6-7
specific gravity: 3.22 for fosterite and 4.39 for fayalite
•Varieties: Peridot,a gem variety of Olivine.
Source
Magnesium rich Olivine is an essential mineral in most ultrabasic igneous rocks.
Olivine is marketed as an ideal rock for
sauna stoves because of its comparatively high density and resistance to weathering under repeated heating and cooling.
The aluminium foundry industry uses olivine sand to cast objects in aluminium.
Olivine is also used to tap blast furnaces in the steel industry, acting as a plug, removed in each steel run.
P.S: I do hope we'll be able to recognize the mineral called Olivine wherever we may find it.
