Expert: Ralph Salier - 7/1/2010

Question
QUESTION: I have a number of questions.Please answer as many as possible according to your expertise.
1.I have seen for sale fossils of ginger and garlic in an antiquity shop.They look like ginger/garlic  but is rock hard. The price is about $8 each,which seems to be very cheap. The shopkeeper says they were found near a cave.
(a)how do I determine whether they are really fossils or not?
(b) if they are really fossils, then they should be thousands of years old,right?
(c) how much do you estimate to be the real value if they are really fossils?
(d) we have a scanning electron microscope in our University.For research and academic purposes, what sort of study would you suggest for me to undertake?
2.I am studying a polished cross-sectional piece of an igneous rock under the SEM.How do I determine which phases/compounds crystallise first(from the molten material) from the micrographs taken?

ANSWER: Hi Noor,

1) I have my doubts about the fossil ginger and garlic.  They may be hard as rock but this can be done by polymerizing the root or perhaps other methods.  They could of course be real, but organics like this tend not to fossilize unless very specific conditions exist for this to occur. For the price, it may be worth buying an example and then examine it under the SEM.  

a) buy one and cut it open.  If it is a fossil, there will be no smell and it will be silicified thought out.
b) If they are fossils, then they are at least 100's of thousands of years old if not millions.
c) Typically it is the rarity and completeness of the fossil that determines its value not just to collectors but to researchers as well
d) I would do comparative studies between the modern and ancient versions to see if there is any obvious changes in the structure or cells.

2) I have a background in geology but it is rather old and unused. But if I recall correctly, those minerals that have the largest crystals in the matrix began to grow first.

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QUESTION: Thank you very much for your answer.Could you please clarify more what you meant by doing "comparative studies between the modern and ancient versions"? Thank you

Answer
Hi Noor,

If they are true fossils then, evolutionarally, these may be very different from modern versions.  Some times the cell structures are preserved in fossils and can be compared to modern examples and from this a comparison can be made.  This may show no, some or a great deal of evolutionary change.