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Jewelry, Gems, & Minerals/determining stone and rock


I am looking for information in determining and identification the type of stones and rocks witch are giving to me to identify at my work. for example I'm given a kind of stone that is said it is marble and I should test it and confirm or reject it. other type of stones that are sending to me include granite, dolomite, travertine ,...
please help me in finding easiest and simplest and cheapest ways of testing them and identifying their nature.
thanks a lot.

ANSWER: Hi Zohre,

This is a more complex question. If your suppliers is limited to only a handful of different stones then we could set up a testing chart that will help you determine the type of rock. For example, marble and travertine will react very readily with dilute acid, unless these are dolomite based (containing Mg). Then they will only react as a powder. Granite will never react to any acid. Dolomite will react with acid only in powder form. Something that looks like dolomite but fizzes readily with acid is most likely limestone.

However, if your suppliers send you a great variety of different rocks and you don't know what you are getting on a day to day basis then your request is ultimately more difficult. Then you should probably take a geology class at a local college to educate you in order to perform your task.

---------- FOLLOW-UP ----------

not many types of stones are sending to. mainly the rocks that I mentioned above are delivering to me. Now how can I set a table for these rocks: marble, travertine, granite, dolomite
Thanks a lot.

Here is a table that might help determining the your rocks. First you will need a bottle of dilute acid. Hydrochloric acid (HCl) works well. A 5% to 7% solution works well. You also need a nail or knife.

When you get a rock, make sure the surface is clean (free of dust). Place a drop of acid on it. If it fizzes, then your rock is either marble or travertine. If it does NOT fizz, then it is either granite or dolomite.
For rocks that do NOT fizz, take your nail or knife and repeatedly scratch a small area to create some powder of the rock. Place a drop of acid on the powder. If the powder fizzes (even slightly), then it is dolomite. If it does NOT fizz, then it is granite.
Now there might be a complication. If your marble and/or travertine contain lots of magnesium they will NOT fizz either with the acid unless powdered. Unfortunately this is not something I can tell you from here. If you want you can send us some samples. We will check it out free of charge and send you a determinative table for your application. Please see for details.  

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Uwe Richard Kackstaetter, Ph.D. (Dr.K)


I can answer questions concerning minerals, mineralogy, gems, metals, and anything that has to do with geology. However, I am NOT a jeweler. Questions about values, settings, gem stone cuts and appraisals are best directed to other experts on this site. I can however aide in the identification of unknown mineral materials. As a public service and part as training for new geoscientists, our university department provides FREE mineral identification for individuals. Please contact me for details or go to for details..


I am a professor of applied geology and mineralogy with many hours of field experience. Furthermore, I enjoy recreational gold prospecting and mineral collecting. As a professor I am engaged in research concerning minerals and their occurrence.

Member of the GPAA (Gold Prospectors Association of America) as well as the Association of Environmental Geochemists. Member of the GSA (Geologic Society of America) Member of the AIPG (American Institute of Professional Geologists)

Here is a small sampling: Mineral-rock handbook: Rapid-easy mineral-rock determination : written for anyone interested in minerals and rocks - Proctor, Peterson, and Kackstaetter;Macmillan Pub. Co. (New York and Toronto and New York) Physical Geology Laboratory e-Manual [CD-ROM], Kackstaetter, Earth Science Education LLC Colorado Front Range Self-guided Geology Field Trips, Kackstaetter,

Ph.D. in Applied Geology and Mineralogy. I am actively teaching courses in mineralogy and a variety of field courses with mineral collecting opportunities. Background in precious metal exploration.

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