|
The Vickers test measures the hardness of a metal by indenting it with one of these super-hard gems |
a diamond
|
$400 |
DJ |
HARD SCIENCE |
2021-04-26 |
#8386 |
|
At 10, this mineral is the hardest on the Mohs scale |
diamond
|
$400 |
DJ |
SCIENCE IS A 7-LETTER WORD |
2013-04-29 |
#6596 |
|
Carbonado is an impure form of this mineral used for drills & abrasives |
diamond
|
$200 |
DJ |
SCIENCE |
1992-02-21 |
#1730 |
|
Bort, an impure type of this form of carbon, is used for cutting, not for jewelry |
diamond
|
$400 |
DJ |
SCIENCE |
1991-05-06 |
#1551 |
|
Heat one of these to 1,500 degrees centigrade in an inert atmosphere & it reverts to graphite |
a diamond
|
$400 |
DJ |
SCIENCE |
1991-04-18 |
#1539 |
|
This mineral comes after No. 9, corundum, on the Mohs scale |
Diamond
|
$800 |
DJ |
SCIENCE |
1990-02-01 |
#1254 |
|
At 15 on the modified Mohs' scale, this substance still has the highest hardness number |
a diamond
|
$300 |
J |
PHYSICAL SCIENCE |
1988-01-11 |
#776 |