Quartzoid crystals from Maine and New Hampshire

Quartzoid is a term for a quartz crystal with no visible prism faces (I'm not sure whether the non-visible prisms are not there or just too small to see) - just the terminations. These are usually found in the micro range of size, and there are a few places they are found. I have seen such from the Palermo quarry, Groton, N.H. and one from Newry, Maine. I think I have seen a reference to another place with such crystals. I was wondering what other sites in this area have had such 'quartzoid' form crystals, and what environments, associations, they occur in or with.

Hi Dana,

The Chickering Mine in Walpole, NH, has quartz crystals in siderite which have very short prism faces. Not sure if they qualify as "quartzoid" or not.

See: Chickering Quartz

Hi Dana,

I have generally heard of Quartzoid or bipyramidal hexagonal Quartz crystals referred to as high temperature Quartz crystals.
In most Me/NH pegmatites they are closely associated with Siderite xls. Usually microscopic sizes. Newry,Bell Pit, Red Hill, Bennett Quarry and Palermo in NH are some of the locations I have noted but no doubt there are others.

Cliff

The quartzoid "prismless" form can occur at low temperature as well as high, according to my mineralogy textbook (Hurlbut and Klein - Manual of Mineralogy). An alternate term that I favor is "Cumberland habit" because it is just that, another habit and most people dont know what quartzoid means. Anyway, Cumberland habit quartz is very common in vugs and fault veins cross-cutting basalt in Connecticut, and not just as micros but up to an inch or more. These are pretty low temperature deposits. Too many localities to list here, I have many in my collection but havent gotten around to photographing examples from those localities yet.

I've also found prismless quartz crystals ("quartzoid" habit according Hurlbut & Klein) in a similar environment to what Harold Moritz describes: crystals that are about 0.4-0.9 cm across in a fault vein in basalt, from the Woodward Ranch in the Big Bend area of Texas. I've posted a picture of one of the specimens on my Mindat website (Bruce T Mitchell), photo # 301858, if you're interested. Judging from Mr. Moritz's description and my own observations, it may be that such crystal-forms are more common with quartz being deposited in extrusive volcanic rocks rather than in pegmatites or sedimentary deposits - I'll be interested to see if more observations confirm this.

These are quite common in Tasmania, mostly coating dolostone cavities, eg. [www.mindat.org]
(this one actually has small prism faces but most don't). They appear to be low temperature in origin.

Regards,
Ralph

Dana,
Bipyramidal quartz crystals are well known from the Chubb Lake, St Lawrence County, NY [www.mindat.org] .
Not quite the New England area (ME + NH), as you have requested, but close...

While carefully sifting through a batch of alluvial Montana sapphire gravel, I found many bipyramidal clear crystals that must be quartz. No apparent prisim faces, but hard to see (the crystals are 1-2mm or so).

I have found small ones in little cavities in greisen areas.