Answer:
A. Obsidian
Explanation:
It fits the property described in the question.
It cools so fast that no visible crystal or grain could form. It has high silica Composition, black and glassy. It is also used to make tools with sharp edges
Be more specific, in order to answer this question.
The proximity of water was an advantage to Western Europe and its culture was able to flourish as a result. Trade and travel by sea were easier and safer in historical times.
The Indus valley thrived between 4000 and 1500 BC