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Exchanging with Italian micromineral collectors.

For its size, Italy has a wide variety of rock types and geological settings. These have produced a surprising number of well crystallized and/or rare minerals and mineral suites. Many of these species occur as superb microspecimens, and Italian collectors have been extremely industrious at seeking them out.

Many Italians collect microminerals as a specialty, while others acquire them to expand species collections. Over the years, I have exchanged microminerals with perhaps two dozen Italian collectors. Several of those with whom I have traded recently, and others who are interested in exchanging by mail, are listed below.

Mr. Roberto Allori viale di Marino, 81 00043 Ciampino Roma, Italy

Mr. Luigi Chiappino Via Palmanova, 67 20132 Milano, Italy

Mr. Giancarlo Galvani Via De Amicis, 35 20123 Milano, Italy

Mr. Claudio Albertini Via Grandi, 22 28026 Omegna (Novara), Italy

Mr. Giancarlo Pierini Via Campigli, 91 21100 Varese, Italy

Mr. Ugo Ostan Via Arenili, 10 26100 Cremona, Italy

Mr. Pier Giuseppe Prandoni Via Roma, 47 20025 Legnano (Milano), Italy

The photographs which follow will show the quality and variety of the micromineral specimens which can be obtained by exchange with these collectors. In many cases, the initials of the person in the above list who sent me the specimen are included in the photo caption.

Samarskite is usually thought of as being jet-black, sometimes altered on the surface to brown or yellow-brown. The microcrystal from Cuasso al Monte shown in Figure 1 appears to be pale tan throughout. There are several quarries on the mountain, the bedrock of which is a quartziferous porphyry looking like granite. The locality is known for samarskite and a variety of other interesting species such as fayalite, gadolinite, zinnwaldite, bastnaesite, synchisite and xenotime.

The hellandite and vonsenite shown in Figures 2 to 4 are from two of three known localities: Km 60 Cassia and Tre Croci. No minerals from the third locality, Le Carcarelle, are shown. The three are quite close together, the whole area being only 7 km in its greatest extent. All three are also closely related geologically since, in each case, the country rock is volcanic ejecta of various types. This is not to say that rare species abound. The interesting minerals are found only in sanidine, which makes up a small fraction of the whole. The percent of "mineralized" sanidine is estimated at 5% of all sanidine, and the fraction of ejecta with well crystallized minerals is about 1%! It is interesting that (a) both the above minerals plus many of the other species found in these rocks contain essential boron and (b) boron is present in significant amounts in many volcanic rocks. Also obtained by exchange from one or several of these localities are many other rare and interesting species such as superb danburite, nosean, afghanite, transparent allanite, tadzhikite-(Ce), green thorite, urano-thorianite, asbecasite, stillwellite-(Ce), transparent brown baddeleyite, tiny red-brown crystals of betafite, very small, dark brown crystals of zirconolite-3T, and beautiful, greenish yellow, transparent crystals of vicanite-Ce.

Monte Cervandone in the Val d'Ossola is the source of many rare alpine-type minerals. Two such are the superb synchisite in Figure 5 and the rare species tilasite [ILLUSTRATION FOR FIGURE 6 OMITTED]. Two other species found on Monte Cervandone, asbecasite and cafarsite, are interesting because they are named for their compositions; the former is an AsBeCaSilicate, while the latter is a CaFeArsenate. Incidentally, a simple and almost completely pronounceable mnemonic allows one to memorize the eight most common elements in the earth's crust in their order of abundance: OsiAlFeCaNaK-Mg.

We turn next to two fairly new minerals named for their (Italian) type localities. The first is cetineite, an antimony oxide-sulfide, from the Cetine mine in Tuscany (see Sabelli and Brizzi, 1984). This beautiful mineral [ILLUSTRATION FOR FIGURE 7 OMITTED], like several of the minerals formed by alteration of lead/silver slags by sea water at Laurium, Greece, is a bit of a cheater in that it too is a slag mineral. Other fine antimony minerals found at the Cetine mine are cinnabar, cervantite, coquandite, kermesite, onoratoite, mopungite, senarmontite, stibiconite and valentinite. Still more exotic species are found: brizziite, rosenbergite, elpasolite and ralstonite. The second namesake mineral [ILLUSTRATION FOR FIGURE 8 OMITTED] is peretaite, another antimony mineral but a hydroxide/sulfate. It is named for its type locality, the Pereta mine (see Scortecci and Tazzini, 1984), although the mineral is also found at the Cetine mine. Operated for stibnite, the Pereta mine is also the type locality for coquandite. Interestingly, coquandite is also found at the Cetine mine!

While Italy does not have the flashy zeolites of India, New Jersey or Australia, it nevertheless ranks high in the zeolite world. The type localities for no less than eight of the approximately 49 known zeolites (barrerite, dachiardite, gismondine, merlinoite, montesommaite, phillipsite, pollucite, and willhendersonite) are within its borders. The Island of Elba is home to the world's finest dachiardite; wagon wheel-like, cyclic eightlings which have never been found elsewhere. Another example of excellent multiple twinning is the wellsite from Monte Calavarina shown in Figure 9.

The Latium volcanic area near Rome is host to a wide range of volcanic minerals similar to those of the better-known Eifel district of Germany and the Monte Somma/Vesuvius complex near Naples. No less than 11 new species have been described from the area in just the last few years (liottite - [ILLUSTRATION FOR FIGURE 10 OMITTED] -, franzinite, sacrofanite, giuseppettite, pitiglianoite, cesanite, vertumnite, rossiite-Ce, tuscanite, merlinoite and vicanite-Ce). The first five of these, plus microsommite, davyne, afghanite and vishnevite, are all hexagonal and members of the cancrinite group. They differ in the stacking pattern of their A, B and C layers. A nice example of tuscanite from the Latium volcanic area is shown in Figure 11. Most of these species, plus excellent microcrys-tal specimens of sodalite, meionite, hauyine and sodalite, are easily obtainable by exchange.

Three minerals from less well known localities follow. The first [ILLUSTRATION FOR FIGURE 12 OMITTED] was given the now discredited name "breislakite." The name is still used by local collectors, as "breislakite" is now known to be either ludwigite or vonsenite, the two occurring together and even as mixed crystals at this locality, and being indistinguishable without chemical analysis. The specimen shown is probably ludwigite, a magnesium iron borate, from the Vallerano quarry. The country rock is a hard, dark gray lava, in veins and vugs of which are found well-crystallized minerals. Note again the presence of essential boron in a species found in volcanic rocks, although ludwigite is found in a variety of other rock types as well. Very fine cahnite crystals are also found at the Vallerano quarry, as are gismondine, leucite, melilite and others.

Second is the specimen of common but beautifully crystallized, acicular aragonite with black psilomelane shown in Figure 13. Inside the globular aggregates of psilomelane are found microspherules of kutnohorite. From Levane, these crystals are contained within what look like tiny geodes. These are found after spring ploughing of the fields.

Last but not least are the deep orange-yellow crystals of saleeite from Arcu Su Linnarbu. Shown in Figure 14, these are superb crystals of a rare magnesium uranium phosphate. Other beautifully crystallized uranium minerals such as bassetite, parsonsite, phosphuranylite and sabugalite are also found at these prospects (see Vochten and Brizzi, 1987).

And now, a word about the size of initial trades. Some traders of microminerals, in addition to sending the specimens requested by a new trading partner, send still more species as gifts. Others, rather than sending a single specimen of a species which has been requested, send as many as a dozen. While in either case they are being generous, their actions raise problems for the people receiving their material. Several other traders to whom I have spoken, and I also, feel it is our duty to send an equal volume of material. In many cases, we do not have sufficient material to do so; and in other cases, we just do not want or cannot use the unexpected material which we had not requested. I feel that it is far better to send only what was requested and, unless otherwise requested, only one of each item in first exchanges. Perhaps in later exchanges, sending gift items specifically labeled as such might be appropriate.

With the above, I reach the end of the first of two columns on trading with Italian micromineral collectors. Part 2 will cover the wonderful minerals of Vesuvius/Monte Somma.

I am greatly indebted to Roberto Allori, an extremely knowledgeable and discriminating Italian collector, for reviewing the rough draft of this column, and for supplying accurate and complete locality descriptions.

Wm. A. Henderson, Jr. 47 Robin Ridge Drive Madison, CT 06443

REFERENCES

VOCHTEN, R., and BRIZZI, G. (1987) Bassetite and other uranium minerals from Arcu su Linnarbu, Capoterra, Cagliari, Sardinia. Mineralogical Record, 18, 181-184.

SABELLI, C., and BRIZZI, G. (1984) Alteration minerals of the Cetine mine, Tuscany, Italy. Mineralogical Record, 15, 27-36.

SCORTECCI, P. B., and TAZZINI, M. (1984) Minerals of the Pereta mine, Tuscany, Italy. Mineralogical Record, 15, 19-26.
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Author:Henderson, William, Jr.
Publication:The Mineralogical Record
Date:Mar 1, 1996
Words:1509
Previous Article:Munich Show 1995.
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