Examining the Student Experience Observation Vs. Inference

Observation vs. Inference
1.round outside (observation)
2.rough on the outside but no jagged edges (inference because other rocks I have touched had a rough texture.)
3.inside is hollow (observation because there is definitely an empty spot inside)
4.inside has jagged, crystal appearance (inference from past crystals I have touched and seen)
5.brownish outside and purple inside (observation)

How did this rock form?
1.Extreme heat caused it to crystallized (inference because heating sugar and water creates crystals when it cools.)

What is it made from? (Neither observation nor inference)
1.It is made from the mineral quartz.

What don't you know about the rock yet? (Neither observation nor inference)
1.what areas of the world it is found in
2.can the average person find this or are there certain clues to look for
3.how large are the rocks
4.is amethyst a delicate crystal