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Sherry
 #1 
My boyfriend works at a rock quarry where they make gravel and such. He brings home these beautiful hunk of rock packed tight with crystals, that I am assuming are quartz, but the majority are covered with dirt, limestone dust, and sandstone dust. I would love to clean them up, but I am afraid of damaging them by knocking the loose chunks of crystal out, or using something that would end up clouding and dulling the crystals. Can someone suggest how to proceed? Oh and some of these things are as big as a size 10 man's shoe.
Bob Harman
 #2 
Welcome to club!     First we will assume that what your husband brings home is a common mineral such as quartz or calcite. It might be something else, but common minerals are just that........common!   Knowing where in the USA the quarry is located would tell us a lot about what might be found there.

As to cleaning the examples. To get the larger pieces of loose dirt, mud etc off, I gently swoosh the example thru room temperature water in a bucket or laundry sink. Then soak each example overnight in the sink or the bucket filled with fresh soapy water. I might add some household bleach to kill any organics, but if none are present, I forgo the bleach.
You mention that the examples may be loose or crumbly etc. If this is really the case, they most likely won't hold up to any (even gentle) cleaning.   But if intact, they will hold up and can be rinsed further with a harder water stream in a day or two.
If the examples are iron stained, that might be your next step, using Super Iron Out, easily purchased at most hardware stores.    I don't use it until I know more about what I am dealing with and as you are new to all this, wait until you see the cleaned examples and get more directions. Trimming your examples or removing unwanted broken crystals might be a further step after evaluating each example.  Hope this helps.    BOB
Alfred Ostrander
 #3 
Sherry,

Welcome to McRocks. If it is all possible, can you post a photo or two? Photos may not always say a thousand words but can be quite helpful. If you are not comfortable saying exactly where your boyfriend is getting these, I understand. Some quarries don't even want employees to take out specimens. However, anything you can share would be helpful.The reason is that different minerals are found in different kinds of rocks. 

You mentioned limestone and sandstone dust. If this is a limestone quarry the crystals could well be calcite. If the quarry is in sandstone, quartz would be likely. And as limestone and sandstone are sedimentary rocks, it is possible both types of rock can be found there. 

For general cleaning, Bob has covered things pretty well. I am not sure what you meant exactly by knocking the loose crystals out. Quarrying operations can knock a lot of crystals loose in a pocket and cause a lot of damage. The best you can do is gently rinse them and see what happens. 

Now for some basic testing. I am sure you have some vinegar or can easily get some. Put a small amount of vinegar in a small bowl. Take some small, clean pieces of the rock and put them in the vinegar. I always gently swish the vinegar around the sample to make sure there are no air bubbles on the piece. Then watch to see if the piece begins to slowly give off small bubbles. The acid in the vinegar will break down limestone. So if it begins to bubble, you have limestone. If it does not bubble, it will be hard to say what the rock is. Now, repeat the process (with fresh vinegar) with some small chips of the crystals. If they begin to show bubbles you probably have calcite crystals. Think of this as your own science project that really won't take much time but might be quite revealing as to what you have.

Of course, you could ask your boyfriend to ask around at work. Someone there will know. I'm a geologist and I do know how to look up geologic information before I go dig somewhere but I always ask people who might know just what I might find somewhere.

Personally, I won't assume anything common about what you have. Given the vast amount of rock out there that does not contain any crystals, I consider finding them an uncommon experience and a whole lot of fun. What I find might not be a rarity. It might not be worth much money. But I always get a big kick out of finding even "common" minerals. Sometimes I don't take any of them home because I already have some from that location and I have to consider that I have a whole basement full of lots of specimens, fossils, rocks, and minerals. That all started over 50 years ago. Some "common rocks" led me to a great hobby and then a career! You are having a great experience with these rocks. Otherwise, you wouldn't have taken the time to to ask about what you might have. So enjoy your finds to your fullest! And if you find out more, Please tell us! And tell that guy of yours to bring you a couple more... You just never know what you might find.

Best Regards,
Al O
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