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In gemmology, there are several destructive tests that are used to identify gemstones. These tests involve physical manipulation or chemical reactions that can alter or damage the gemstone. Here are some of the destructive tests commonly used:
- Fizz Test: This test involves dropping a small amount of dilute acid on the gemstone. If the gemstone fizzes or produces bubbles, it indicates the presence of carbonates.
- Scratch Test: The scratch test involves using a harder material, such as a diamond or corundum, to scratch the surface of the gemstone. This test helps determine the hardness of the gemstone by observing the scratch mark it leaves.
- Streak Test: The streak test involves rubbing the gemstone against an unglazed porcelain tile to observe the color of the streak it leaves behind. This test helps identify the gemstone’s true color and distinguish it from surface coatings.
- Hot Needle Test: This test involves heating a fine needle and touching it to the gemstone’s surface. It helps identify heat-treated gemstones by observing the reaction, such as color changes or fractures caused by thermal shock.
- Fracture Test: The fracture test involves subjecting the gemstone to a controlled amount of force, such as hitting it with a hammer. This test helps identify the gemstone’s toughness and resistance to breakage.
- Cleavage Test: The cleavage test involves applying pressure to the gemstone to observe its response to controlled splitting along its natural crystal planes. This test helps identify gemstones with distinct cleavage properties.
It’s important to note that these destructive tests should only be conducted by trained professionals and as a last resort, as they can potentially damage the gemstone. Non-destructive tests, such as visual examination, optical properties analysis, and specific gravity measurements, should be performed first to minimize the need for destructive tests.
On today’s Unboxing, Elizabeth is back and it’s time for more gem science experiments! Once again, we have a series of fantastic specimens, but this time we’re going to destroy them…to show you 6 tests gemologists and geologists use to identify gems in the field. Learn how to fashion an octahedral fluorite with a hammer, what gemstone breaks like wood, and whether amber smells better than copal. Fizz Test: 1:36 Scratch Test: 3:43 Streak Test: 6:20 Hot Needle Test: 8:37 Fracture Test: 11:44 Cleavage Test: 15:11
Do you enjoy science? Do you enjoy destruction? If you said yes to either of those questions, then you are in the right place! In this week’s episode, Rob and Brittany exploit some of the physical weaknesses of gemstones. With flames and hammers, they will conduct experiments on gemstones like opal, copal, peridot, fluorite, and more! Which stones will survive? Watch to find out!
Organic Gem Materials
Natural coral, shells, and pearls are carbonates. Since they release a protein smell from hot point testing, you can’t use that test to distinguish them from plastic imitations. However, you can identify them by observing their reaction to acid.
Warnings
This is a potentially dangerous procedure for both the stone and the tester. Exercise great care. Keep in mind that acid testing is a destructive test that should only be conducted as a last resort.
Always Add Acid To Water
AAA – Always Add Acid to water! Never the other way around. If you pour water in acid, it will boil and splash out of the container. The acid will burn metal, wood, skin, etc. Memorize the AAA rule.
Pearl Warning
Since there are non-destructive ways to separate natural pearls from their imitations, acid testing isn’t recommended for pearls.
Necklace Alert
When acid testing a strand of beads, make sure you don’t get any fluid on the cord. The acids used for identification will damage cords.
Do Not Use Full-Strength Hydrochloric Acid
Full-strength hydrochloric or muriatic acid isn’t recommended for gem testing. Diluting full-strength acids