WHAT ARE THE MISCELLANEOUS NON-VISUAL PROPERTIES?

"Hmmmnnn!! A grab-bag of properties! Lulu, what are you talking about?!"
"I'm talking about a whole collection of properties that minerals can have that can be useful in describing and identifying them! Not properties that you can see when you look at minerals, like color and shape, but properties that you can't see!"
"Such as?!"
"Taste, smell, magnetism, reaction to acid, elasticity!"
"Taste and smell, OK! But the others - magnetism, reaction to acid, elasticity, you can see them!!"
"True! You can see the effects of magnetism, reaction to acid, etc., but not just by looking at the minerals! You have to perform a test - such as applying a magnet or adding a drop of acid - before you see the property!! It's like testing for hardness or streak!"
"You win!! Tell me about these properties!"
"Well, taste and smell are pretty obvious!! Not many minerals have a taste, but those that do are pretty distinctive! And some minerals smell if they are smashed or heated! Those with sulfur can smell like rotten eggs or a burnt match; those with arsenic, like garlic!"
"Sounds good! What else!"
"Well, talking about sound, there's one mineral that if you hold it in your warm little paw, it gives off a cracking sound! The reason is that the mineral doesn't transmit heat very well! When you hold the mineral, the outside warms up and expands, while the inside remains cold and doesn't expand! And as the outside expands, it breaks away and separates from the inside, giving off a cracking sound!"
"Minerals that have iron in them can be affected by strong electro-magnets! And the mineral magnetite, as the name suggests, will respond to even a weak hand magnet! And there's one variety of magnetite, called "lodestone", that actually is a magnet! The ancients used lodestone as a compass to navigate the seas!"
"Now tell me about acid!"
"Minerals that are carbonates will give off carbon dioxide when put in contact with dilute hydrochloric acid!"
"What would I see?!"
"If the reaction is strong, the drop of acid will bubble like mad! For some carbonates, the reaction is weak unless you powder the mineral first! When you powder the mineral, it lets the mineral get into better contact with the acid by creating more surface! Just like you can get a sugar cube to dissolve faster if you break it up!"
"Neat! And elasticity?!"
"Well, like a rubber ball! If you squeeze it, it springs back to its original shape! That's elastic behavior!"
"There are rubber minerals??!!"
"No! But if you bend thin sheets of some minerals slightly, they do spring back to their original shape!"
"And for those minerals that possess one or more of these non-visual properties, they can be very helpful in identifying the mineral! Go to the Miscellaneous Non-Visual Features Testing Lab and look at the examples and definitions of these properties."


© 2010, David Leveson/Revised by G. Rocha and Michelle O'Dea