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Search found 602 matches |
Author | Message |
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Topic: 2 Unknowns co-occurring with Caledonite, Grand Reef Mine, AZ | |
Pete Richards Replies: 4 Views: 1463 |
Forum: What is it? - Where is it from? Posted: Mar 27, 2024 19:47 Subject: Re: 2 Unknowns co-occurring with Caledonite, Grand Reef Mine, AZ |
I wonder if the violet-grey mineral might not be cerussite or anglesite. The luster is suggestive. | |
Topic: Trying to find information on rose/pink quartz and tourmaline associations. | |
Pete Richards Replies: 17 Views: 3758 |
Forum: Minerals and Mineralogy Posted: Feb 29, 2024 09:55 Subject: Re: Trying to find information on rose/pink quartz and tourmaline associations. |
I used Mindat to search for rose quartz. Under associations there are listed 16 images of rose quartz with schorl. 12 of these would be of interest to this thread; all are from Taquaral, Itinga, Min ... | |
Topic: Identification of my mineral | |
Pete Richards Replies: 11 Views: 2663 |
Forum: FOR BEGINNERS: What is it? Where is it from? Posted: Jan 29, 2024 20:12 Subject: Re: Identification of my mineral |
To my eye, your first pictures look like carbonate (probably calcite), but the last one looks like a rim of quartz around something else, maybe more carbonate. There are little reflective spots in yo ... | |
Topic: Can some please let me know what you might think this is? | |
Pete Richards Replies: 6 Views: 2909 |
Forum: FOR BEGINNERS: What is it? Where is it from? Posted: Jan 05, 2024 12:16 Subject: Re: Can some please let me know what you might think this is? |
To clarify for someone who is probably a beginner: fluorite is a naturally-occurring mineral composed of calcium and fluorine atoms in a regular arrangement. A fluorite crystal has directions of wea ... | |
Topic: Rhodochrosite Locality near "Flagstone, CO" | |
Pete Richards Replies: 4 Views: 2977 |
Forum: What is it? - Where is it from? Posted: Dec 28, 2023 14:22 Subject: Re: Rhodochrosite Locality near "Flagstone, CO" |
I can find no evidence for the existence of Flagstone as a place name of any kind anywhere in Colorado. Mindat lists two mines/claims with Flagstone in the name, but has no mineral list for either. ... | |
Topic: Please Help Me To Identify This Stone. | |
Pete Richards Replies: 17 Views: 5932 |
Forum: FOR BEGINNERS: What is it? Where is it from? Posted: Dec 16, 2023 11:15 Subject: Re: Please Help Me To Identify This Stone. |
To all appearances this is a rock, not a single mineral. In addition to other problems/questions about the XRF data, it is at best a bulk composition that will not correspond to any particular miner ... | |
Topic: Fluorite crystallography? | |
Pete Richards Replies: 27 Views: 11517 |
Forum: Minerals and Mineralogy Posted: Dec 13, 2023 09:42 Subject: Re: Fluorite crystallography? |
(snip)
The thing is, and this may be part of the problem, these cube faces seem relatively smaller than the obvious large one. Yes, definitely. These crystals show substantial deviations from ide ... |
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Topic: Fluorite crystallography? | |
Pete Richards Replies: 27 Views: 11517 |
Forum: Minerals and Mineralogy Posted: Dec 12, 2023 20:52 Subject: Re: Fluorite crystallography? |
I am not sure how to interpret Jesse's fluorite. I cannot see any view that is unambiguous. It appears that the cube faces are clear, maybe slightly pebbled, and that the other faces are frosted.
... |
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Topic: Fluorite Star | |
Pete Richards Replies: 3 Views: 3832 |
Forum: Minerals and Mineralogy Posted: Nov 28, 2023 20:06 Subject: Re: Fluorite Star |
Fluorite – Mercedes-Benz Star
(snip) My question to you, particularly Pete, are these triangles compatible with section (111) of the dodecahedron? I must say I am not very comfortable trying to i ... |
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Topic: Fluorite crystallography? | |
Pete Richards Replies: 27 Views: 11517 |
Forum: Minerals and Mineralogy Posted: Nov 28, 2023 13:40 Subject: Re: Fluorite crystallography? |
(snip)
Larger overgrowths tend to be on the octahedral terminations with smaller ones down the octahedral edges and even smaller ones stepping all over underlying octahedral faces. Bob's comments ... |
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Topic: Fluorite crystallography? | |
Pete Richards Replies: 27 Views: 11517 |
Forum: Minerals and Mineralogy Posted: Nov 28, 2023 08:35 Subject: Re: Fluorite crystallography? |
So it is {100}{110}.
Yes, it is {100}{110}. I checked my small collection of Naica fluorites last night, and mine also have this habit. An interesting extra is that some of them have an overall o ... |
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Topic: Fluorite crystallography? | |
Pete Richards Replies: 27 Views: 11517 |
Forum: Minerals and Mineralogy Posted: Nov 27, 2023 13:49 Subject: Re: Fluorite crystallography? |
Toby’s post presents a question that puzzles many collectors, and the answer is not always immediately evident. We have a cube (100) modified by the octahedron (111) or the rhombic dodecahedron (110) ... | |
Topic: Dissolution enables dolomite crystal growth near ambient conditions | |
Pete Richards Replies: 9 Views: 5379 |
Forum: Mineralogical Literature Posted: Nov 24, 2023 10:10 Subject: Re: Dissolution enables dolomite crystal growth near ambient conditions |
I think it is appropriate to ask "what really is The Dolomite Problem"? I think the term is attractive enough and vague enough that different people may have different answers because they ... | |
Topic: Locality for sphalerite and white mineral | |
Pete Richards Replies: 1 Views: 3805 |
Forum: What is it? - Where is it from? Posted: Nov 02, 2023 13:28 Subject: Locality for sphalerite and white mineral |
Here is an old specimen, probably 19th century, of sphalerite and a white mineral. There are two specimens in the collection with catalog number 2260, reportedly from Joplin, Missouri. However, the ... | |
Topic: About cyclic twinning - (5) | |
Pete Richards Replies: 157 Views: 281582 |
Forum: Featured Columns of FMF Posted: Aug 30, 2023 07:32 Subject: Re: About cyclic twinning - (5) |
Excellent point, Bob! | |
Topic: About cyclic twinning - (5) | |
Pete Richards Replies: 157 Views: 281582 |
Forum: Featured Columns of FMF Posted: Aug 27, 2023 13:29 Subject: Re: About cyclic twinning - (5) |
I am confident that this is a twin, a hexagonal sixling like the drawing. The main difference is that the pits shown in the drawing have been filled in on the actual specimen.
I can imagine distor ... |
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Topic: Poudrette Quarry: Carletonite | |
Pete Richards Replies: 7 Views: 14564 |
Forum: Mines and Mineral Localities Posted: Aug 27, 2023 12:58 Subject: Re: Poudrette Quarry: Carletonite |
I concur. This is probably rhodochrosite, which was found often at the Poudrette Quarry, including in this habit. Warm hydrochloric acid on a little flake would confirm that it's a carbonate, and th ... | |
Topic: About cyclic twinning - (5) | |
Pete Richards Replies: 157 Views: 281582 |
Forum: Featured Columns of FMF Posted: Aug 24, 2023 10:53 Subject: Re: About cyclic twinning - (5) |
Thanks for a wonderfully careful search for the provenance of this unusual rutile twin. I am struck not only by your effort, but by the importance of the availability on line of literature such as Po ... | |
Topic: Combining two hobbies | |
Pete Richards Replies: 9 Views: 10202 |
Forum: Off-Topic and Introductions Posted: Jun 27, 2023 13:37 Subject: Re: Combining two hobbies |
That is a very nice cabinet. Please say something about its dimensions and the lighting arrangement. | |
Topic: An idea for a collection | |
Pete Richards Replies: 20 Views: 15140 |
Forum: Minerals and Mineralogy Posted: May 11, 2023 09:01 Subject: Re: An idea for a collection |
In a sense, the whole question of what LLMs (Large Language Models) can tell us (about mineral evolution) is marginally off-topic, but it is too interesting and too important to discard as such! I pa ... | |
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