So here are our test results.
I will list the correct designated SG/RD for each mineral
after the heading.
Quartz- SG/RD, 2.65
Quartz Crystal;
Dry7.44 - Wet4.64 = 2.80. 7.44/2.80 = 2.65
Polished Quartz;
Dry5.32 - Wet3.31 = 2.01. 5.32/2.01 = 2.646
Topaz- SG/RD, 3.4 - 3.6
Dry8.24 - Wet5.90 = 2.34. 8.24/2.34 = 3.521
Pyrite- SG/RD 4.9 - 5.2, average 5.0
Dry17.84 - Wet14.12 = 3.72. 17.84/3.72 = 4.795
In this test our results for the Pyrite is the only one that
falls considerably outside the designated range. This makes
me want to look up the SG/RD for other possibilities such as
Marcasite or Chalcopyrite.
And one final test.
Pictured below is a cabochon I made out of some of our
local pink Feldspar. There are many types of Feldspar and
I have assumed this would be an Orthoclase.
First I looked up the designated SG/RD for a few types
of Feldspar.
Anaclime- SG/RD 2.2 - 2.3
Orthoclase- SG/RD 2.5 - 2.6
Plagioclase- SG/RD 2.62 - 2.76
Test results on the cabochon;
Dry5.27 - Wet3.20 = 2.07. 5.27/2.07 = 2.5458
Which places it firmly within the range of Orthoclase.