Spinel stone is found in "Sri Lanka" / "Madagascar" / "Afghanistan" and "Brazil",

It is characterized by the following physical and chemical properties:

Physical properties

• The shape is octagonal
• Group minerals oxides / igneous rocks
  
• White scratching
• Bear heat
• Hardness 7.5 / 8
• The color is red
• radiant
• Transparent / semi-transparent
• Vitreous sparkle

Chemical properties

• Refractive index 1.73 / 1.71
• Density 3.6
• The chemical formula is aluminum oxide / magnesium
• Not dissolve