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List of
rocks I have worked with:
I learned this agate-polishing method from Paul "GeodeKid" Calburn and since I was originally interested in polishing only agates so I'm limited in what type of equipments I have. But now I'm starting to expand to other materials. Here's the list of what I have worked with so far.
Due to lack of experience or certain tools, I don't do any form of jewelry or cabochons, sorry. Maybe someday....
I can't work on any materials harder than Moh's hardness of 7 such as garnets, corundum (rubies/sapphires), tourmaline. Likewise for those with different mineral compositions such as granite and jade.
I'm developing a method to polish the likes of Malachite and Petoskey Stone (Moh's Hardness is 3). I can give them a good polish but at higher cost due because it takes more work to to polish those types of rocks.
Watch out for any porous materials which may will not take a good polish. Test the cut surface with a drop of water which will darken that spot. If the spot stays dark after wiping water off, it's porous, thus lower polish quality. Another way is to observe the color change when wetting the piece. More dramatic the color change, more porous it tend to be. Just because that piece look great when wet doesn't mean that it'll look good dry and polished. The water can hide any fractures and defects so please keep that in mind when buying any slabs for specimen purposes.
If you don't see a type of rock listed here, feel free to ask me or send it to me for me to give it a try.
Type of Rock: Polish Quality?
Notes of Concern:
Agates, any types: Excellent
The concern is is that Braiilian Agate SLABS/Slices are generally sensitive to the stress of being grinded and polished that they may develop some fracturing. The halves or thick pieces are no problem as long as they don't contain too much calcite in them. Excessive Calcite reduces the traction needed to get better polish.
Apache Rhyolite: Satin polish often with mixed results.
That material is generally porous, thus harder to get good polish.
Bertrandite("Tiffany Stone"): Good polish
More silica, better the polish.
Chalcedony: Excellent
Datolites, porcelian type for Michigan: Very good.
I can easily polish Michigan datolites.
Dinosaur Bones: Mixed results
More agatized the piece, better the polish. I tend to use acid to etch calcite so that it won't interfere with polishing process. I won't take any pieces containing excessive calcite (test with acid). There are also other softer minerals that can reduce the traction needed to get good polish so expect some mixed results.
Dolimate, Wave: Satin polish
Too soft to be well-polished with my agate-polishing method. I might do better when I'm in Michigan
Charoite: Good
I'm surprised that my method works on that material given its different mineral compositions.
Labradorite: Failed
That's a type of feldspar that did not work well with my agate-polishing method. Same reason why I had trouble with granite.
Larimar: very good.
I can work with those pieces.
Granite: Failed (poor result)
Made of different minerals with different Moh's hardness, won't work well with my methods.
Jade: Failed (poor results)
That material is made of several different types of minerals so my method won't work good on them.
Jasper, Biggs: Mixed results
A soft jasper type enriched in iron mineral stains that can reduce traction need to get better polish. More agatized (or less porous), better polish. Check their porosity with a drop of water.
Jasper, Blue Mountain: Excellent
Slabs are more sensitive than agate slabs. Check for any fractures.
Jasper, Bruneau: Excellent
Slabs are more sensitive than agate slabs. Check for any fractures.
Jasper: "Bumblebee". poor polish
It's actually a travertine mixed with silica and calcite so my method won't work well on that one. Plus that it tend to contain toxic minerals
Jasper, Carrisite: Excellent
Jasper, Deschucates: Mixed results
A soft jasper type enriched in iron mineral stains that can reduce traction need to get better polish. More agatized (or less porous), better polish. Check their porosity with a drop of water.
Jasper, Indian Paint: Poor, too porous.
Indian Paint Jasper is "soft jasper" which is too porous to polish.
Jasper, Morrisonite: Excellent
Slabs are more sensitive than agate slabs. Check for any fractures.
Jasper, Ocean Jasper: Excellent
Classic Agatized pieces are the best. Jasperized pieces will take good polish
Jasper, Willow creek: Excellent
-Slabs are more sensitive than agate slabs. Check for any fractures.
Jasper, Pilbara: Good
That type from Australia is "soft jasper" and bit harder to work with due to its varying porosity
Jasper, Purple Elephant: Excellent
Jasper, Spider-Woman: Good
"Soft jasper" type. Somewhat porous but can work with that material.
Jasper, Sahara Nodules: Good
That kind of jasper has better silica content then Deschucates Jasper so better polish.
Kabamby "Jasper" (not true jasper), actually marble, satin polish.
Lapis Lazurli: Failed
Can't do that one because of several different minerals mixed in it.
Larimar: Good polish when using a differnet method, so it'll cost more.
Malachite: Good Polish (different method)
Since I have to use different method, it'll cost more. More solid, better the polish.
Obsidian: OK
I can polish them but their polish may won't be as good as agates.
Cpal, common (opalite): Very good.
Can polish most types of opals such as those from Australia and Peru.
Opal, Spencer: Very Good.
Peitersite: Very good
As long as they're well-agatized, I can polish those.
Petrified Wood, many types: Variable
More agatized it is, better the polish. Some petrified woods may be too porous/pitted to work with.
Petrified Wood, Arizona: Excellent
Petrified Wood, Blue Forest: Mixed polish results:
Some are solid, some are porous, thus harder to get good polish. More agatized, better polish.
Petrified Wood, Palmwood type: Excellent
Petoskey stone: Satin Polish
Too soft to be well-polished with my agate-polishing method. I might do better when I'm in Michigan
Picture Jasper: Variable
There are many different kinds of picture jaspers with different silica contents. More silcified the piece is, better polish. Disaster Peak jasper is too porus to be polishable.
Picture Jasper: Disaster Peak: Too porous to be polishable.
Picture Jasper; Owhyee creek: very good
A type of jasper with higher silica content, easier to polish.
Quartz, Amethyst, Chevron, Excellent
Quartz, Amethyst Lace, Excellent
Quartz, black-tourmaline: Excellent
They're more sensitive than agates so I can't do the slabs.
Quartz, Rose: Excellent
They're more sensitive than agates so I can't do the slabs. I tried and they fell apart.
Quartz, Rutiled: Excellent
They're more sensitive than agates so I can't do the slabs. I tried and they fell apart.
Rhodenite: Failed (poor result)
Rhodochraste: Satin polish
Too soft to be well-polished with my agate-polishing method. I might do better when I'm in Michigan
Silkstone: Poor. TOXIC (Asbestos), I won't work with that material.
They contain traces of asbestos, making it a hazardeous material.
Sodalite: Satin Polish
More blue color, better the polish
Sonoran Rhyolitre/Jasper, poor polish, too porous
Tiger-Eye/Hawk-Eye: Excellent but expect some pitting
Turquoise: mixed results depending on their hardness:
Harder the piece, better the polish but won't match with agates' polish quality
Utah Septarians: Satin Polish
They are made of calcite so I'm not good with those.
Variscite: Good
Semi-soft stone so expect to see some scuffles on grossy polished surfaces.
Zebra Marble: Failed
Some people mislabel that material as Zebra Agate. It's actually made of calcite so I couldn't polish that one well.
