S.No.

Month

Stone

Hardness

Specific Gravity

Refractive Index

1

January

Garnet

6.5 -7

3.5

1.73 - 1.75

2

February

Amethyst

7

2.65 - 2.91

1.544 - 1.553

3

March

Aquamarine

7.5 – 8

2.67 – 2.84

1.57 – 1.6

4

April

Diamond

10

3.52

2.42

5

May

Emerald

7.5 - 8

2.67 - 2.84

1.56 - 1.59

6

June

Pearl
Alexandrite

2.5 - 4.5
8.5

2.68 - 2.85
3.5 - 3.8

1.630 - 1.695
1.745 -1.757

7

July

Ruby

9

3.9 - 4.1

1.76 - 1.78

8

August

Sardonyx
Peridot

7
6.5 -7

2.61
3.31 - 3.48

1.54 - 1.55
1.650 - 1.695

9

September

Sapphire

9

3.9 - 4.1

1.76-1.78

10

October

Opal
Tourmaline

5.5 - 6.5
7 - 7.5

1.42 - 1.47
3.0+

1.37 - 1.47
1.62 - 1.68

11

November

Topaz

8

3.4 - 3.5+

1.61 -1.64

12

December

Turquoise

Lapis Lazuli

5-6

5.5 - 6

2.6-2.9

3.1

1.61-1.65

1.61 - 1.64