|
Post by snowmom on May 23, 2014 11:40:01 GMT -5
agates confuse me! I suppose because some of the things I see named as agates are so different. I know they are supposed to have bands, and that they are supposed to have translucency in at least part of them. I have looked at good websites explaining them but still not sure.... are at least some of these agates? The largest is about the size of a tangerine, all have swirly sorts of stuff, are extremely hard and have at least a spot of clear or nearly clear on them. all are collected locally and have suffered the ravages of Lake Huron or the glaciers which made the lakes or at least glaciers which transported them. Some of my confusion may be because worn rocks look so different from the ones freshly dug out of a vein somewhere. I am aware that agates from the great lakes area are much different than what is found elsewere. Maybe that is part of my trouble. Not the best photos, all were wet, tried to get them in the sun. The one I think is an amethyst is not hard to pick out, and it has just a bit of what looks like banding too. I have never seen as dark a purple as in this stone, but it still glows and shouts purple when in the sunlight. any input you all can share will be valued and thanks in advance for being ready to point me in the right direction.
|
|
Sabre52
Cave Dweller
Me and my gal, Rosie
Member since August 2005
Posts: 20,466
|
Post by Sabre52 on May 23, 2014 15:37:54 GMT -5
Looks like most of what you have is quartzite. The first pic appears to be a quartzite breccia. Far right of your last pic does appear to be a banded agate or at least a white banded chert. The purple stone is interesting. I've seen blue quartzite but not dark purple. We have pale purple here in Texas but the colors in yours are much more saturated. Cool piece! Not amethyst as amethyst is purple crystalline quartz and your specimen appear more like quartzite in texture.....Mel
|
|
|
Post by mohs on May 23, 2014 15:49:12 GMT -5
collection of color ! that purple is serious
|
|
Deleted
Deleted Member
Member since January 1970
Posts: 0
|
Post by Deleted on May 23, 2014 16:01:38 GMT -5
I don't know what they are but great finds! I'd be excited to find anything that cool around here
|
|
|
Post by snowmom on May 23, 2014 16:57:11 GMT -5
the purple is quartzy to look at and even has a little strip of deep purple druzy crystals on it. I do think the first photo is breccia of some sort, posted that one by accident. I think the white one on the far right might be a fossilized tooth... remember all of these have considerable beach and glacier wear which smooths and 'fuzzes' up the surface of all the stones. I do think some are feldspar/quartzy but the clear spots which show the lines beneath them maybe mean they tried to become agate or I find so many impossibly mixed stones up here. I despair of ever getting the names straight. Guess it won't matter so much if I am just going to polish/tumble them and look at them for 'pretty'. thanks anyways!
|
|
Fossilman
Cave Dweller
Member since January 2009
Posts: 20,685
|
Post by Fossilman on May 30, 2014 9:20:46 GMT -5
The first one is totally awesome!!! They all should shine up great!!
|
|
transcendental
spending too much on rocks
Member since June 2014
Posts: 459
|
Post by transcendental on Jun 12, 2014 9:26:31 GMT -5
Agates are my favorites, they are extremely difficult to id if they don't have obvious banding. jasper and chalcedony being the 2 well known rocks in the same familly as agates. Minerals like quartz, manganese, moganite, augite,limonite..... list goes on and on of individual elements that give different mineral composition, colors, and patterns found in agates. If your interested I found a really good article on agates trying to id and learn more about them. Also do a Google search for microscope images of quartz, chalcedony, Jasper and agate and can familiarize yourself with characteristics to help to id what you find yourself if you have access to a microscope, even magnifying glass can help if you can see growth patterns and the crystal structure. Another way to id is with shortwave uv. If you dont have one ... they arent cheap, contact a local university. The geology dept may have one you can use. I contacted the Yale peobody museam about a month ago to id some rocks with their uv lamp. They were very happy to help. Quartz won't glow, only reflect the light from the bulb, chalcedony ( a main component of agate) will glow green unless it has an iron content which will block any uv reaction. Hopefully this is helpful and you can have some fun news.psu.edu/story/140648/2001/09/01/research/how-do-agates-form
|
|