Announcement

Collapse
No announcement yet.

What type of stone am I working with

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Tam
    replied
    Very true . I think you could easily sell these .

    Leave a comment:


  • Kaz
    commented on 's reply
    Thanks Tam. I'm glad you like them. Used to work with wood a lot, even making my own fishing lures. Eventually I figured out that I can work these stones with the right tools. I've gotten better at it over time but I still impress myself sometimes and often wonder how did I do that. The most important thing to me is that when I am done it's not just a fish but recognizable as a certain type of fish. It's kind of cool thinking that since you're making something out of stone that sometime in the future it could be somehow considered an artifact.

  • Tam
    replied
    I just saw this and am so impressed with those fish I can’t get over it . They are spectacular to me .
    Then listening to painshills explanation of the rock type is always a treat .
    Loved getting asked what I am doing and I start reading it out loud and the look on the faces were priceless .
    Great thread and Kaz you are talented

    Leave a comment:


  • Kaz
    replied
    Just for fun

    Click image for larger version

Name:	IMG_4866.JPG
Views:	72
Size:	73.9 KB
ID:	409722

    Leave a comment:


  • painshill
    replied
    It’s going to be a toughie to identify from pictures and the truth is that some rocks don’t even have an accepted individual common name because they fall within a spectrum of compositions with no definitive boundaries. ‘Trap Rock’ is a good example, in that it covers any dark-coloured, fine-grained, non-granitic intrusive or extrusive igneous rock of a sub-volcanic nature. That’s even what your material might be. Perhaps in the territory of a diabase (US terminology) or dolerite (in the rest of the world). These kinds of rocks may also be altered to varying degrees by metamorphism such that it’s even more difficult to name them.

    Long Island itself is rather poor with respect to the diversity of its rock types but there is a large intrusive diabase sill forming the New Jersey Palisades on the Hudson River, near New York City. It’s clear that your cobbles have seen a lot of water tumbling and that also means they might have arrived from somewhere quite distant which opens up a much larger world of possibilities. Although Long Island has a poor diversity of native rock types, it has a lot of ‘erratic’ rocks which have come from the Northwest and from over the Canadian border. Those arise from a mixture of glacial transport (mostly large boulders) and transport of smaller broken material by glacial meltwater rivers, in some cases creating localised moraine deposits of smoothed stones.

    I haven’t really much more to add, but here’s a couple of things you might try to help narrow it down. Hold one of those stones in the palm of your hand and give it a sharp rap with the wooden handle of a hammer or a screwdriver. Do you get a resonant ‘chinggg’ sound as you might get from a glass, a short-lived ‘chink’ sound as you might get from a ceramic mug, or just a dull clunky thud? The broken surface doesn’t show any sign of angularity and just looks randomly uneven (is that correct?) but if you hold it in some very directional light (eg strong sunlight coming through a window) do you see anything sparkly catching the light if you rotate the rock in your hand?

    We may never know what it is, or perhaps may be able to broadly classify it but without finding an appropriate agreed name for it.

    Leave a comment:


  • Kaz
    replied
    Something for Halloween.

    Leave a comment:


  • Kaz
    commented on 's reply
    North shore of Long Island

  • Hoss
    commented on 's reply
    some type of sedimentary rock Kaz. what area did you say you find these pieces?

  • Kaz
    replied
    Well pretty sure it's not cannel coal. Streaking left no marks It has no smell and fire had no effect on it. Here is another look at the stones as I found them. The ring I was working on developed a crack so I never finished it. The other broken test piece shows what the interior of the stone looks like. I even hit the pointed end with a map gas torch for a few seconds and it did nothing.

    Leave a comment:


  • Kaz
    commented on 's reply
    Wow thanks for your compliments and for sharing some of your knowledge with me. I will try and test the stone and will let you know what I find.

  • Cecilia
    replied
    I dig up coal often here (not as often as quartz, quartzite, granite, and scoria), and though clearly not knappable, never considered carving. Guess those pendants don’t hang heavy ‘round the neck! I tried knapping once, and almost put out Dog’s eye. But if find big enough piece of coal, may try carving (whittling?). I’ll be aiming for triangle or another basic shape, so don’t worry ‘bout competition, Kaz........yuk yuk!

    Leave a comment:


  • painshill
    replied
    Beautiful work Kaz. You have a real talent.


    It certainly looks like cannel coal (also known as candle coal) to me (not “channel coal” as suggested earlier in the thread… that’s just a misspelling). There is absolutely no possibility that you could get flint to carve like that.

    In American terminology, flint is a higher grade of chert but geologically they’re both cryptocrystalline or microcrystalline quartz varieties with a splintery breakage which is unsuitable for carving. By contrast, “cannel coal” is a hydrocarbon-rich shale which has been subjected to folding or heavy stress such that any laminated structure it originally had has largely disappeared.

    It does have a conchoidal cross-fracture (much weaker than flints or cherts) but it forms in massive cubical blocks with a compact grain that makes it very suitable for carving. Apart from the organic content, it generally has a low silty mineral content derived from mud that’s a mixture of clays and tiny fragments of quartz and calcite but doesn’t have the cryptocrystalline quartz structure of flints or cherts. As such, it’s not a hard rock and will not readily scratch window glass (unlike flints or cherts).

    The organic component derives largely from decomposition and fossilisation of water-deposited plant spores, pollen grains and microscopic aquatic plants and animals. Jet, which can be carved in a similar fashion, forms in much the same way from higher orders of plant life and is a variety of cannel coal.

    There are some easy ways to check if it is cannel coal. If you streak it on the unglazed back of a porcelain tile (any oddment left over from a bathroom refurb will be suitable) it leaves a characteristic ‘greasy’ streak which is usually dark brown or brownish black. You need to blow away any dust and examine the streak itself.

    The name ‘cannel’ derives from middle English dialect for ‘candel’ (candle) and reflects the observation that it ignites and burns readily (how readily depends to some extent on the actual organic content). Even just streaking it may release a petroleum-like odour, but if you hold a flame to it (on a thin edge) then it will char, smoulder or burn with a yellow flame and release an even more characteristic odour. Generally, it produces little or only moderate amounts of ash with a greyish-white colour.

    It was mined on Long Island by the Long Island Company from at least 1860, but I think the remaining deposits are now commercially exhausted.

    If it doesn’t pass the tests above, then we’ll need to re-think.

    Leave a comment:


  • tomclark
    replied
    Man, that is great work, Kaz! I wonder if that black rock is basalt or diabase, both used in ancient and modern sculpture/art? Strange only found one spot but you got supplies!

    Leave a comment:


  • Kaz
    replied
    A few new ones.

    Fluke, redfish and sheepshead

    Leave a comment:


  • Carolina Hunter
    replied
    I'd like to get a few of those for Christmas gifts this year.

    Leave a comment:

Working...
X