FMF - Friends of Minerals Forum, discussion and message board

[Peter Megaw]

After perusing Olaf Medenbach's superb treatment of the fundamentals of optical petrography (See: Off Topic and Introductions: "the most exciting..." thread) it occurred to me that there is an even more basic optical tool that is frequently under (or mis) used both by geologists and mineral collectors...the Hand Lens.

I am eternally grateful to my Geology 301 Intro class TA, Tim Cejka, who told us that if we were serious about studying geology the most important tool we could acquire was a good hand lens. He then showed us how to use one right...hold the lens up to your eye first (the cheekbone makes a great stabilizer for your hand), tilt you head back to keep good light on the specimen and then gradually bring the specimen up to the lens until it comes in to focus. Amazing how many trained geologists don't do this right! At the next level my TA, Ken Nemeth, taught us to first look at thin sections, and the rock they were cut from, with a hand lens as a valuable intermediate step between "outcrop" and microscope]. Ultimately the hand lens becomes the most valuable routine tool in field work...and an invaluable aid in visual geochemistry and mineralogy when picking over old dumps.

The real kicker was the "good" part. The student bookstore sold only the 10X cheezoid "Ruper-Duper" made-in-Japan models with the huge chromed body and singlet optics only slightly better than a piece of busted pop bottle. Ruper's top of the line model, only somewhat smaller than a Cadillac, featured a giant 10x lens on one end and a smaller 20x lens on the other...equally crummy at both ends as we learned on calibrating one that the 10x was really about 7.5x and the 20x was under 15x. Ruper-Duper's and their ilk are still prevalent, although now made in China and sold under a wide range of names for under $20, despite clearly being identical pieces of junk. You see them all over most mineral shows...many in the hands of folks who think nothing of spending thousands of dollars on their mineral specimens! (Their usual argument is that they have a tendency to put their lenses down and walk away from them, which causes less anguish when the lens is a cheapy. A lanyard or chain is a permanent solution to this problem)

The next step up feature duplex lenses...two pieces of glass with different indices of refraction sandwiched together to diminish distortion. These tend to be housed in a heftier cadium or glossy silver or gold-tone plated brass housing and are often used as corporate logo-embossed "gimmes". These are a huge step up from the Rupers, but still fall far short of what can be obtained for serious users.

Until recently, the best hand lenses going were the Hastings Triplet (three pieces of glass with different properties sandwiched together to further reduce distortion) made by Bausch and Lomb. Pricier, (around $50) these come in 10, 14 and 20x with light weight, but durable metal and plastic housings. Lens size diminishes with increased magnification...the 20x is miniscule. This is done so that only an undistorted field is presented....B&L's cheaper Coddington duplex line approaches this problem by inserting an opaque diaphram into the housing to mask off the distortion plagued edges of the lens. The end result is that the Hastings 20X lens has such a tiny field of view that you have to pre-scan at a lesser magnification to identify the grain you then want to focus in on at 20x...too fussy for my taste. I always found the 14x provided a nice balance between magnification and field of view, but of course the 14x often turned out to be harder to find.

Within the last 10 years or so, a new manufacturer has entered the market, producing by far the best hand lens I have ever encountered...once I got one I hung up my B&L's forever! The story goes that they are hand-made by a Japanese craftsman in his basement...I am dubious...but they ARE scarce and frequently back-ordered. Marketed under the name IWAMOTO, these are 20x, broad field lenses, fully corrected for spherical and chromatic abberation. The field is larger than that of the Hastings Triplet 10x, with zero distortion across the entire field..it absolutely revolutionizes what you can see in a hand sample, in a gemstone, or mineral specimen (like those tiny cracks filled with "restoration" materials). They are more expensive than a B&L (about $100 including S&H from Miner's Inc. in Riggins Idaho...what I believe to be the only US suppliers. I get no commission) and come in a significantly heavier mounting. (I had the thick plated brass sides of my original replaced with attractive silver plates which weigh a whole lot less). The only problem I have experienced (beyond having to completely recalibrate my eyeballs) is that the lock rings that hold in the lenses can loosen and the lenses fall out. Torquing them down with a tiny drop of locktite solves that problem...apparently forever.

If you're a routine hand-lens user, the IWAMOTO will change your life...you will see more and better...although you will have to get used to how small some of what you see really is. If you're not, one will open new worlds to you...identifying those tiny minerals in the vugs in the matrix of your recent Tsumeb, Ojuela or Tiger acquisition; checking for damage, repair or restoration on that potential purchase; or exploring the worlds of inclusions lurking in the interior of gemstones and crystals (infuriate your jewler who insists that 10x is the standard for recognizing inclusions). For many the investment will yield far greater returns than a similar amount invested in a single specimen...and it might even lead to examining things under progressively higher magnification!

[mmauthner]

I wish I had talked to you about the earlier or you had written this earlier. About a year ago I too, hung up (rather, relegated to the car glove compartment so I always have a lens around) my 14x B&L Hastings, which was always attached to my collecting/geo vest. I was talked into buying a GemologyPro 10x 20 mm by Schneider. It is intelligently designed, rugged and edge to edge crystal clear; the best I had ever come across, BUT...3 x the price of the IWAMOTO and still only 10x.

Looking forward to trying out an IWAMOTO.

Mark

[Matt_Zukowski]

Over time, and with increasing frustration with the small field of view of "nice" hand lenses, I eventually settled on a cheap plastic duplex with a 3.3 cm lens that I got from the local surveyors shop. The hand lens that you recommend maybe just the ticket. Just ordered one. Thanks for letting us know.

[renpagan]

It looks like Peter has found the hand lens of my dreams. I have ordered one a few minutes ago. If and when I get it, I plan to have iridium new plates ....

Renato

[Peter]

Muchas gracias Peter
One is ordered!

[Peter Megaw]

Now I wish I DID get a commission...on second thought, Renato, I think I deserve one of your irridium flanked jobs as reward for turning you on to these lenses! (Best to A by the way, from me and L...now 5' 9" tall!). Gold, Platinum, Ruthenium flanked versions equally welcome from the rest of you...

Here are some pictures...front and back, our US and Mexican logos...of how we tricked these out for our geologists (we WANT them to see as much as possible)...and a few VERY special friends/supporters (EJHJr.). You can see how easy it is to replace the side plates, the rest is up to your imagination...be cool to see a set with the 6 (7) crystal systems on the sides. Steve and Nancy Attaway, where are you?

Cheers

[Ed Huskinson]

Thanks Pete. I treasure mine, keep it on my little study table in the mineral room, ready for action. I still use Hastings 10X and 14X in the field, don't care if they get all beat up. But this one, with the silver sides and IMDEX scorpion engraved, I use it always I'm mineralizing. S'nice 'cause it's so easy on the eyes, and for a guy who earns his living either with his feet or with his (in my case, left {OD}) eye, it is particularly useful, because I find myself able to spend more time looking at the little details of my specimens without tiring.

Gracias por todo, y amigos siempre.

Lalo

[alfredo]

And then there was the time out in the field when my lens fell irretrievably into a fumarole and I spent the rest of the day using a drop of water on a stretched out piece of a clear plastic bag. Water had the annoying habit of dripping off. Optics left something to be desired too, but the price was right.

[Peter Megaw]

We'll have to start calling you Alfredo McGyver...Potentially a useful trick for starting a fire in extremis, or lighting a fuse for a blast as well...

[Jon Mommers]

Peter

you should definitely be on commission, Miners Inc has completely sold out and are now taking back orders
Thanks for the heads up have been looking for a replacement for my old Triplex

Cheers
Jon

[Jon Mommers]

Thanks Ed as well, also always enjoy your posts.

[Jon Mommers]

Peter

Iwamoto arrived today, the optics are unbelievable. I did not realise just how poor the optics were in my current handlens
Thankyou Cheers
jon

[Peter Megaw]

In the interests of full disclosure...Miners was apparently so overwhelmed by the orders for the Iwamotos that they sent me a 10X lens with internal LED lighting as a thank you. The optics are good to good plus, but the lighting is excellent...would be incredibly useful underground or poor light situations. The lighing is blue biased which might be a problem in some situations and the thing is huge and heavy...not likely to become a routine field tool like the Iwamoto.

I'm trying to figure out if I can combine the two and illuminate the Iwamoto!

[Matt_Zukowski]

Yes, got mine too...way cool. Good for closeups.

[jimB]

I want a hand lens that lays flat in my pocket. Meantime I use a 10X from the jewelry trade. I think I would like a 7X as light transmisson is brighter and depth of field deeper.