Asked by Diamond

three pairs of mineral samples are brought to you for testing. Both samples in one pair look like gold, but one is pyrite, or fool’s gold. Both samples in the second pair look like emeralds, but one is nonprecious apatite. Both samples in the third pair look like rubies, but one is a less valuable garnet. Use the information in the table to complete the dichotomous key to identify each mineral.

Mineral Color Hardness
Gold Metallic gold 2.5–3
Apatite Blue, green 5
Pyrite Metallic pale brass, gold 6–6.5
Garnet Red, deep red, brown 6.5–7.5
Beryl Bluish green, green 7.5–8
Corundum Red, deep red 9


Dichotomous Key

The mineral has a metallic luster. ……………………………………………. Go to 2
The mineral does not have a metallic luster. …………………………. Go to 3
The mineral can scratch at least one of the green stones. …….
The mineral can scratch neither green stone. ………………………..
The mineral is green. ………………………………………………………………..Go to 4
The mineral is not green. ………………………………………………………...Go to 5
The mineral can scratch at least one of the red stones. ………..
The mineral can scratch neither red stone. …………………………....
The mineral can scratch only one of the green stones. ………...
The mineral can scratch both green stones. ……………………….....

All Answers 1

Answered by GPT-5 mini AI
Completed dichotomous key (with identifications):

1a. The mineral has a metallic luster. → Go to 2
1b. The mineral does not have a metallic luster. → Go to 3

2a. The mineral can scratch at least one of the green reference stones (i.e., can scratch apatite). → Pyrite
2b. The mineral can scratch neither green stone. → Gold

3a. The mineral is green. → Go to 4
3b. The mineral is not green. → Go to 5

4a. The mineral can scratch the other green specimen (i.e., it can scratch apatite). → Beryl
4b. The mineral cannot scratch the other green specimen. → Apatite

5a. The mineral can scratch at least one of the red reference stones (i.e., can scratch garnet). → Corundum
5b. The mineral can scratch neither red stone. → Garnet

(Uses hardness values: gold 2.5–3, apatite 5, pyrite 6–6.5, garnet 6.5–7.5, beryl 7.5–8, corundum 9.)