Weight, Density and Specific Gravity

Question 1

How much does 1ct weigh?

Answer 1

0.2g

Question 2

How much does 5cts weigh?

Answer 2

1g

Question 3

What is density?

Answer 3

The weight of a material in grams compared with its volume in cubic centimetres. This is dependent on its composition and structure, how heavy its atoms are and how closely packed together they are.

Question 4

How do you test the density of a gem stone?

Answer 4

Density of a gem compared with the density of water.

Question 5

What is the density of water?

Answer 5

One gram per cubic centimetre 1g/cc

Question 6

What does specific gravity mean?

Answer 6

The ratio of the weight of a substance to the weight of an equal volume of water

Question 7

How do you calculate specific gravity?

Answer 7

Divide the weight of a material by the weight of an equal volume of water.

Question 8

What is hydrostatic weighing?

Answer 8

Used to determine specific gravity by comparing weights in air and water. Spring balances are used ti weigh materials of approx 10g upwards. (water needs to be 4 degrees)

Question 9

How do you use a spring balance?

Answer 9

1. Weigh object in air
2. Weigh object in water
3. A/A-W = SG

Question 10

What is heft?

Answer 10

How heavy a stone feels in your hand

Question 11

How do you measure the SG of a gem that is set?

Answer 11

Using a dial or digital gauge measure width, length and depth. Also note the style of cut.
Measurements should be taken to 2 decimal places and n mm

Question 12

What is Archimedes principle?

Answer 12

An object totally immersed in a fluid experiences an upward force equal to the weight of the water it displaces