Scratch hardness

Material
Material
Mohs' scale
Ridgway's scale
Wooddell's scale
talc
talc
1
1
-
gypsum
gypsum
2
2
-
calcite
calcite
3
3
-
fluorite
fluorite
4
4
-
apatite
apatite
5
5
-
orthoclase
orthoclase
6
6
-
vitreous silica
vitreous silica
-
7
-
quartz
quartz
7
8
7
topaz
topaz
8
9
-
garnet
garnet
8.92
10
-
corundum
corundum
9
-
9
fused zirconia
fused zirconia
-
11
-
fused alumina
fused alumina
9.03–9.065
12
10
tungsten carbide
tungsten carbide
9.09
-
12.0
silicon carbide
silicon carbide
9.13–9.17
13
14.0
boron carbide
boron carbide
9.32
14
19.7
diamond
carbonado
9.82
15
36.4
diamond
ballas
9.99
15
42.0
diamond
bort
10
15
42.4

Question: What are Wooddell's scale values for quartz, corundum and diamond bort?
Answer: Wooddell's scale value is seven for quartz and nine for corundum, and 42.4 for diamond bort.