lesson created by janey cohen for the santa barbara museum
TRANSCRIPT
In Puja and Piety, stone is one of the most universal ma-
terials used to make sculptures, shrines, and votives. It is
part of Hindu belief that if a stone is shaped into a func-
tional object, it becomes filled with a sacred essence
and is used as part of puja (worship). Even stone un-
changed by human hands can be held as sacred. In
thousands of temples throughout India, svayambhu, a
natural, uncarved stone, is the primary murti, or
embodiment of the Divine. For over 2500 years,
sculptors have been using stone as their medium. By
knowing which stone would work best for their
purposes, early artisans were able to create these
enduring works of religious art.
Lesson created by Janey Cohen
for the Santa Barbara Museum of Art
ROCK ON!
Temple Sculpture with Dancing Ganesha. The popular God of Auspiciousness, distinguished by his elephant head. India, Uttar Pradesh, 11th century.
Sandstone. Lent by Anonymous in Memory of Ann Witter.
Did you know that every
mineral has a set of
characteristics that is unique
to that mineral alone and
can be used to identify it? By
learning to test for traits such
as hardness and luster,
streak and density, you can
be a geologist right in your
own backyard.
Head of Shiva. India, Uttar Pradesh, Mathura, 6th century. Mottled red sandstone. Santa Barbara Museum of Art, Gift of Pratapaditya and Chitra Pal, 2008.47.5
Collect several “mystery” minerals.
Try finding different rocks from
your yard or from a rock collector.
Choose minerals that have not
gone through a rock tumbler.
Give each of your minerals a
number. Use this chart
to keep track of the
characteristics of your minerals.
Mineral # Luster Hardness Streak Density
(g/ml)
You will need:
Several samples of unknown minerals
Magnifying glass
Penny
Lamp
Steel nail
White bathroom tile
Glass plate
Kitchen scale that uses grams
Water
Graduated cylinder
Rock On!
Detail of Temple Sculpture Representing Enshrined Bodhisatva Manjushri Seated on a Lotus, Uttar Pradesh, 11th century. Cat. 165.
Luster Test– The appearance of certain
minerals changes when you shine a light on
them. This reflected light is called luster. Use
the light and the magnifying glass and look
at the surface of your mystery mineral. Use
words such as dull, metallic, glassy, or sparkly
to describe the luster.
Streak Test- Take the piece of white tile and
put it on a flat surface. Push the mineral
down onto the surface and rub it across.
Does it make a streak? Write down the color
of the streak.
Hardness Test- First, use your fingernail to
see if you can scratch your mineral. If you
can, it is less than 2.5 on the hardness
scale.
Try to scratch the mineral with the penny.
Does it make a mark on the rock? If so, the
mineral is under 3.5 on the hardness scale.
Try scratching it with the nail. If it gets
scratched, it’s under 5.5 on the scale.
Finally, if your mineral didn’t get scratched
by any of the first three items, use the
mineral itself and see if it will scratch the
glass. Put the glass on a flat surface and
use the rock to scratch the glass. If it does,
it’s over 6 on the hardness scale.
Density Test- Finally, you’ll test the density of
your minerals. First, find the mass of your rock
with a scale in grams and write it down.
Next, fill a graduated cylinder half full of
water. Note the level of water in milliliters.
Carefully place the rock in the water. Note
the new higher level of water that the rock
has displaced.
Calculate how many milliliters of water the
rock displaced. Divide the mineral’s mass in
grams by the volume of water in milliliters to
get the density of each mineral.
Solving the Mystery– Compare your results to
these common minerals and see if you
might have any close matches. If your results
don’t match these, try doing an Internet
search using the words
“properties of minerals”. properties of minerals
Mineral Luster Hardness Streak Density (g/ml)
Graphite Metallic 1 Black 2.1-2.3
Halite Glassy 2.5 No color 2.2
Calcite Glassy 3 No color 2.7
Magnetite Dull 5.5-6.5 Black 5.2
Pyrite Metallic 6-6.5 Gold 4.9-5.2
Feldspar Glassy 6-6.5 Different Colors 2.5-2.75
Quartz Glassy 7 Different Colors 2.6-2.7
Sandstone Dull 6 Light colored 2.2-2.8
Why do rocks and minerals have different
characteristics? They’re made out of different
elements that are put together in different
crystal structures.
You may have chosen quartz in your
experiment. This common mineral is made from
silicon dioxide (silicon and oxygen).
A diamond is made out of pure carbon. So is
graphite. The difference is that their crystals are
not organized in the same way. It’s like taking
an equal number of blocks and arranging them
in different ways. They make different structures,
but they’re still the same blocks.
A gander from Nagarjunakonda stupa. Andhra Pradesh. 2nd century.
A sculptor needs to take into
account all of the characteristics of
a stone before beginning to work
with it.
Stone comes in many lusters and colors, and this will affect
the overall beauty of the piece. In ancient times, before
transportation made it easy to move stone around, the
density of the stone was also a very important factor in
choosing stone. Centuries ago, sculptors simply needed to
use the rock that was natural to their locale.
The hardness is the
most important
characteristic.
Ease of carving is
important, and
softer rock is easier
to sculpt, but it
needs to be hard
enough not to
break and to hold
up over time.
This presentation was created by SBMA for instructional use only
and is not to be altered in any way, or reproduced without at-
tribution
Lesson created by Janey Cohen, Santa Ynez Valley High
School, for the Santa Barbara Museum of Art
For further information about these or other Education and
Outreach Programs, contact Rachael Krieps at
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