The origin of the mezuzah is from the "Shema" in which is mentioned the core beliefs of Judaism and its teachings. Therefore, the "purpose" of the mezuzah is as a reminder, when entering and leaving the home, of the mezuzah's message.
The mezuzah contains a parchment inscribed with a passage from the Torah (from Deuteronomy ch.6 and ch.11), placed on Jewish doorposts.
There are two parts of the Mezuzah, The Mezuzah Scroll itself and the Mezuzah Case. The Mezuzah Scroll is made with ink on parchment of a Kosher animal. The case can be made of almost any material as its purpose is to protect the scroll. Most common materials for the mezuzah case are metal, stone, wood and glass.
There is no limit to the size of a Mezuzah. Attached is a video of the largest known mezuzah recently installed at Ben Gurion Airport.
There are two parts of the Mezuzah, The Mezuzah Scroll itself and the Mezuzah Case. The Mezuzah Scroll is made with ink on the parchment of a Kosher animal. The case can be made of almost any material as its' purpose is to protect the scroll. Most common materials for the mezuzah case is Metal, stone, wood and glass. I attached a link with showing mezuzah cases in different materials.
The scroll inside the mezuzah is written in Hebrew.
The Mezuzah was not "found". The Mezuzah is a Jewish ritual object whose origin is from the Torah, which dates back to 1313 BCE. I guess you could say it was found then.
A Mezuzah case, is the protective and/or decorative case used to cover the Mezuzah Scroll. The Mezuzah scroll is a small parchment scroll that contains biblical passages, which is then place on the door post of homes according to Jewish Tradition. I'll attached a link of some cases so you can see what they look like.
The significance of the mezuzah is all in the mezuzah scroll itself and therefore, when you hang a visible mezuzah scroll, there is no need for any symbolism. However, when you hang a mezuzah scroll in a protective case through which the scroll is not visible, it should have a letter "shin" (looks like this "\|/" ) on the front to indicate that there is mezuzah scroll inside and it is not just a nice case. The Shin is the first letter of the biblical paragraph written within the scroll as well as the name of g d Sha-dai. Having said that, there are many who choose to have various judaic symbols depicted on their mezuzah cases such as the Jewish star, hamsa, tree of life or other as shown in the attached link.
The mezuzah is not a reminder, but the fulfillment of a commandment or mitzvah - that found in Deuteronomy 6:9, which tell us to inscribe the words of the Sh'ma blessing upon the doorposts of our houses.
No
Yes, if it's directly outdoors.
The Talmud describes a dispute regarding the proper placement of the Mezuzah whether it should be horizontal or vertical. As a compromise it's placed in between the two, on a slant.
The proper way to hang a Mezuzah is on the right doorpost, when entering a room. It should be placed at the bottom of the top third of the doorpost height. It should be at a slight angle (about 15 degrees) facing inwards, towards the room. It should be installed using nails, screws, adhesive or other permanent installation method.