WARD'S NATURAL SCIENCE BULLETIN. 
3 
Pseudomorphs. 
While minerals — as compared with organic 
products — are the most stable of substances, the 
stability is one of degree rather than of kind. 
The changes constantly going on around us 
affect the mineral world as well as the organic, 
although the visible results are often of a widely 
different character. Mineral matter may thus 
undergo a partial or complete change in its con- 
stituent elements while retaining a specific out- 
ward form; or again, it may suffer a molecular 
change of physical properties yet preserve its 
original outward form. To either of these 
changes is applied the term pseudomorphism and 
the products are called pseudomorphs, a name 
proposed by Hauy to cover all such observed 
cases of mineral matter which are, as it were, 
masquerading under forms not their own. 
According to the methods by which the pseu- 
domorphs were formed they have been divided 
into: 
a. Pseudomorphs by replacement or substitu- 
tion. 
b. Pseudomorphs by infiltration, or incrusta- 
tion. 
c. Pseudomorphs by chemical alteration. 
d. Pseudomorphs by urn's, Par alteration, 
witiiout change of coin position, for which the 
specific term of pumworphs has ;• ..-u provided. 
In pseudonioi phs by rep: each molecule 
of the original substance as fast as removed, is 
repalced by a particle of the w ingredient, 
which thus reproduces the r m - 'St texture of 
the former Of this kind of psemiomorpli silici- 
fied wood is the most common, example. 
Pseudomorphs by i,p ■ », occur when 
a mineral substance fills a cave/ which has been 
formed by the removal of a previous one. The 
new mineral is thus iuerally east in the ready- 
made natural mold furnished by the disappear- 
ance of the original mow) as. Pssip.-'omorphs by 
incrustation are largely me: uslkurs of quartz or 
calcite over other mm, : is and the subsequent 
removal of t|$£ incnish-'d r . ; cal leaves hollow 
moulds which may again helmed by infiltration. 
The pseudomorphs by ■- are a large and 
interesting class which may be subdivided into 
such as have been altered through the loss of in- 
gredients; by the add-on of ingredients; or by 
an exchange of ingredients. Thus Gay-Lus- 
site (rSTasGOa-f- Gt 003 -g§ aq) by losing the 
sodic carbonate and water, rpemnes Calcite (Ca 
Go s) retaining the Gn v v-L c-ite form of crystals. 
Similarly Cuprite (OusO) by loss of oxygen is 
altered to Native Copper (Cm). Where alteration 
takes place by the addition of substances these 
are most commonly osygen, water, or carbonic 
acid. So Anhydrite (CaSQo by the addition 
of two parts of water is changed to Gypsum (Ca 
SO 4 + 2 Hs O;) and Cuprite by the addition of 
water and carbonic acid becomes Malachite. 
When alteration is due to an exchange of some 
constituents as in Feldspar (Alsus, K 2 O, 6 
Si O 2 ), by an exchange of part- of the silica and all 
the potash for a certain amount of water, we 
have a transition into Kaolin (AI 2 O 3 , 2 Sio’ 2 , 2 
H 2 O); or in siderite (Fe CU;n, by exchanging 
carbonic acid for water there is the well known 
change into Limonite (He F<A O^). In all these 
cases the last-formed product exhibits the crys- 
taline form of its prototype. 
In the case of paramorphs these are limited to 
the few mineral substances which naturally crys- 
talize in more than one form (dimorphic), such 
as calcic carbonate, titanic acid, etc. To this 
class belongs the Caleb e altered from Aragonite 
at certain temperature-. 
Alteration in its various forms generally takes 
place from the exterior, and gradually proceeds 
inwards until the change is completed. By 
breaking open one of the familiar pseudomor- 
phous Malachite crystals from Chessy, the un- 
altered centre of Cuprite is usually exposed to 
view. 
Pseudomorphism has occurred on a large scale 
in nature as in the alteration of Feldspar to Kao- 
lin; palcite to Gypsum; Anhydrite to Gypsum; 
Augite to Rensselaerite— noteworthy examples 
of the last two kinds are at Bex, Switzerland; 
and St. Lawrence Co., N. Y., respectively— and 
afford many fascinating problems in chemical 
geology. The remarkable products of pseudo- 
morphism formerly consigned to an obscure cor- 
ner in collections are regarded as of gi;eat scientific 
value and have in consequence become the 
objects of earnest and increasing attention. 
F. W. 8. 
Of these interesting bodies we have among 
others the following forms on hand: 
METALLIC. 
PSEUDO. 
MORPH. 
Hematite. 
FORM 
IMITATED. 
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LOCALITY. 
Pyrite, Cumberland, Eng. , $1.50 
“ Magnetite, Nova Scotia, 2.50 
“ Calcite, Ilmenau, Thuringia, 2.50 
Limonite. Calcite, Werfen, Tyrol, 1.00 
“ Calcite, (Scalenohedrons) Cornwall, 
Eug., 1.25 
Calcite, near Raschan, Saxony, .75 
Calcite, (Thin removable shell capping 
Calcite), Missouri, .75 
Siderite, Dobschau, Hungary, .75 
Siderite, Hiittenburg, Carinthia, .75 
Siderite, Pike’s Peak, Col., .75 
Marcasite, Washington Co., 
Mo., .50, .70 
Penn. & Missouri, 
Cumberland & East- 
bourne. Eng , Ariege 
and Bougival, Fr. , 
Dobschau & Dog- 
nacska, Hungary, 
Elba; Viol ho on 
the YVeser & West- 
phalia, Get 1 ., .05, 1.25 
Wad. Calcite, Hiittenberg, Carinthia, 8.00 
Galenite. Pyromophite, Germany, .80 
“ Pyrargyrite, Prussia, 2.00 
Sinithsouite. Calcite, Min, .50, 2.00 
Malachite, Cuprite 1 single crystals), Chessy, 
France, .50, 1.25 
EARTHY. 
Calcite. Aragonite, Herrengrund, Hungary, .50 
Aragonite, Girgenti, Sicily. .80 
Gay-Lussite, Eiderstadt, Ger., .15, .25 
“ Gypsum, Wurtemberg, 2.00 
Orthoclase, Tliuringa, .15, .25 
Pyrite, 
(Single detached 
Crystals and 
Groups). 
SILICATES. 
Steatite. 
Pyrophyllite. 
Serpentine. 
Chlorite. 
Glauconite. 
Pinite. 
Oligoclase. 
Rhodonite. 
Quartz. 
Enstatite, Bamble Norway, 40, 100 
Chiastolite, N. H., .25, .85 
Scapolite, Snaruin, .50, 1.25 
Garnet, Michigan, 1., 1.25 
Pyroxene, Fassa, Tyrol, .50 
Ioiite, Manzat, Auvergne, .80 
Leucite, Bohemia, .80, .50 
Willemite. New Jersey, 8.00 
Calcite, Trcdell Co., N.C., .10 1.00 
Calcite, Hudson River, N. Y., 1.00 
Calcite, Loling, Carinthia, 1.00 
Calcite, Schneeberg, Saxony, .75 
Argillaceous Sandstone. Halite, Rhenish Prussia, .75, 2.00 
SILICEOUS PSEUDORMORPHS OF OR- 
GANIC MATERIAL. 
( Phyto mo rphs, Zoo morph s — N aum. ) 
Quartz after Wood, El Paso Co., Col., .25, .50 
Milam Co., Texas, .15, .30 
“ Petrified forest,” Egypt, . 25, 2. 00 
India, 5.00 
Micraster, Charlton, Eng., .50 
Echinoderm, France, .35 
Chalcedony after Coral, .50, 1.00 
“ “ “ Tampa Bay, Fla., .30, .70 
Opal after Wood, Nevada Co., Cal., .25, 1.10 
“ after Wood, Kohibach, Hungary, .40, 1.50 
“ “ “ Tasmania, .75, 1.50 
Since the above was in type we have sent a 
full series of these Pseudomorphs to Professor 
Williams of Cornell University. 
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We can supply nice Quartz Crystals, inclosing 
movable drops of fluid, for from $1 to $3. Also, 
beautiful specimens of opalized wood from Cali- 
fornia and Nevada, and good Native Loadstone 
from Arkansas, for from 25 cents to $1. 
t IV 
MINERALOGY. 
Our new material in this department comprises 
a series of magnificent 
STIBJSTITES 
From Japan; 
“HELL FIRE ROCK” 
From Utah; 
From the Tyrol. 
An unusually fine lot of APATITE TITAN- 
1TE, ZIRCON and DAWSOMTE from Canada. 
BORAX and SlLiOlEiED WOOD from Cal- 
ifornia. 
ULEXITE from Nevada. 
A large series of beautifully perfect and modi- 
fied QUARTZ CRYSTALS (some containing 
fluid) from Little Falls, N. Y,, Hot Springs, 
Ai k , Nevada and Switzerland. Fine specimens 
of 
XVII JLi.X_.E3 HIT E3 
From Antwerp and St. Louis. 
(tARNIERITE from Oregon. 
CORUNDUM from India and North Carolina. 
TOURMALINES from' Brazil. 
ZEOLITES from Bergen Hill. 
GUANA J UAT1TE from Mexico. 
NATIVE LODESTONE from Arkansas. 
TURQUOiS from New Mexico. 
CANCRAN1TE of extra quality, from Maine. 
Some beautiful 
ARAGONITES 
From Australia. 
SPINELS 
From New York. 
CROCIDOLITES 
From South Africa, and some choice Carvings 
AGALMATOLITE 
From China. 
MINERAL COLLECTIONS. 
The utility of object teaching is now no longer 
questioned. In all branches of Natural History 
the material for ocular demonstration is indis- 
pensible, and in no department has this come to 
be more fully recognized than in Mineralogy and 
Geology. But what is wanted is not merely a hap- 
hazard gathering of miscellaneous fragments, but 
typical characteristic series, systematically ar- 
ranged, aud varying in extent with the amount of 
time to be devoted to the subject and the thorough- 
ness with which it is to be pursued. Such col- 
lections are properly the work of a lifetime if 
each specimen is gathered singly, as is apt to 
be the case, unless unusual facilities are availa- 
ble, facilities generally possessed only by national 
museums, and not always even by them. 
