Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-04-26
EXHIBIT INCLUDES
EVERY KNOWN ROCK
Nantz Collection of 1000
Pieces Is Declared Most
Valuable of Kind.
Special Dispatch to The Star.


/ STATE COLLEGE, Pa. April Is
/ Specimens Of every known rock as
sombled in one small room and weigh
| ing altogether less than two tons are
| owned by Pennsylvania State College,
and the collection is believed by scien-
| lists to be the most valuable of its kind
! in existence.
| 1t is known as the Krantz collection
! of rocks AND was obtained more than
/ 90 years ago by Dr. Marshman E.
! Wadsworth, at one time dean of the
School Of Mines and Metallurgy at the
college. 1t comprises more than 1000
specimens of rock gathered from all
parts Of the world and because of its
unexcelled value in the study Of rock
structures is estimated to be worth
more than 100000. DR.. A. p. Homes.
associate professor of geology is in
charge Of the collection and has added
to 1t from time to time.
Thin Sections Aid Study.
The rock specimens may be consid-
cred as only one part of the valuable
collection. For each rock specimen
there is thin section to be employed
IN microscopic studies. These thin sec
! tons OF rock are of greatest importance
in studying texture and rock and min
eral genesis, and are made by grinding
rock fragments to sufficient thinness to
permit light to pass through freely.
The standard thin section is approx
1mately 3 millimeters in thickness and
when made as a permanent mount for
/ microscopic use it is cemented to q
| glass slide of convenient size Such q
slide can be kept almost indefinitely for
classroom use. The Krantz collection
| includes 1000 thin sections which are
used to supplement the rock studies.
Basis of College Work.
| The, collection stands today prac-
| tically' as it was first obtained, COM
plete and In excellent condition It is
used as the basis of all undergraduate
and graduate study in Photography at
/ the college.
Roughly, the assemblage of rocks may
/ be grouped in three major divisions
! igneous. metamorphic and sedimentary.
The igneous division comprises approx
mately 2l00 specimens, all of which
were formed from molten solution at
great depth within the eartfs crust
and were intruded into the upper por-
lions OF the crust as bikes or sills. or
were poured out upon the surface of the
earth as enormous lava flows, or blown
out by volcanic force as ash frag-
ments
! vi Inc lgneOuS types about 700 are
plutonlc, or are known to have formed
at great depths under conditions of
slow cooling. About 40 Dare of intru-
sive or porphyritic character and the
remainder Of the igneous group. about
1000 in number, are fine grained types
representing laVas and volcanic glasses
and ash OF varied chemical composition
formed under surface conditions.
300 Metamorphic Specimens.
The metamorphic group represents
| an assemblage of well crystallized rock
| specimens Of varied composition and
! texture numbering 300 units, all of
which are characterized more or less
/ from pressure at low temperatures
such as schists states and gneisses.
The third group consists of approxi-
mately 1000 specimens known as sedi-
mentary rocks. These are formed at
normal temperatures through the
agency Of water or wind and are for
most part residual accommodations in
shallow seas, which subsequently be-
come lithified, such as sandstone, shales
and limestones
Although the collection as whole
Is largely European, it represents rock
specimens from all parts Of the globe,
collected and labeled with scientific care.
The collection is assembled in heavy
| freproof steel cases, arranged accord
/ ing to the Rosenbusch classification.
and each specimen is carefully labeled
as to identity and locality from which
| 1t was taken.