What’s the difference between 8th house Mercury and Mercury in Scorpio?

[Charles]

How would these two placements be expressed differently?

Discussion

[The-Bard]

Vastly different.

Signs don’t equal houses.

How it differs would entirely depend on the composition of the entire chart.
Mercury in Scorpio is in the sign that belongs to Mars. How’s mars doing in aforementioned chart? And what house is Mercury Scorpio in?

Mercury in the 8 could mean a lot: but what sign is it in? What houses do Gemini and Virgo fall in? These are the signs ruled by mercury, so that would tie it all together.

These placements mean nothing without context.

[making_plans_for_]

If Mercury is how people talk and think, the sign where it is in the natal chart tells us more about the way they do it (scorpio-like) and the house is more about the topics it shines its best in.

For example: 8th house mercury in Aries will have a different flavor than in taurus, and talk maybe more forceful (aries) about things like death, transformation, debts, financial investments etc. (8th house themes) while a taurus mercury is more calm and strategic about those things. It also depends of course on other aspects and the rest of the chart.