When is a tomb a mausoleum?

I must have had an inkling, on the 30 October walk through Waikumete Cemetery, that Matthew Gray, in his continuing series on the graves in West Auckland for the Western Leader, would include this one. Then again, the gravesite of the Buchanans of monumental masion fame was of interest anyway that night. I would write a letter to the Western Leader along the following lines, but as Gray is also the newspaper's editor, my comment may not necessarily be printed there. On grounds of pickiness, more than anything else (he is, actually, a nice chap).

In his article printed Tuesday 9 November (today), he wrote:

It is also significant as the first above-ground vault -- also known as a mausoleum, to be constructed in the graveyard a few years after its [Waikumete Cemetery] opening in 1886.

Now, there's bound to be those of you out there who would agree with Gray that a below-ground burial is just a grave (but is also at times a vault if the coffin is within something else, but still below ground) and that anything above ground is also a vault as known as a mausoleum. Perhaps the four columns carved into the monument help constitute it as a mausoluem. But, when I think of mausoleums, I think of this:

Image from Wikipedia, under  Creative Commons Attribution-Share Alike 3.0 Unported license.

or this:

I'd call the Buchanan monument a tomb or an above-ground vault, rather than a mausoleum. But in the end, we are all dust to dust and ashes to ashes, so the semantics I guess are meaningless. I'd welcome your thoughts.