I like to browse the web and look at pretty stuff that I have no means of buying. Lately I’ve been looking at emeralds. The really spectacular ones cost thousands and thousands of dollars.
Sometimes, on ebay, I see rather large emeralds, said to be natural Colombian, and described as “Museum Grade” or “Museum Quality.” Google has not provided me with an adequate explanation of what this means. One site said it meant high quality, but the ones I’m seeing on ebay have a ridiculously low price, which caused me to think maybe it means this is a good gemstone for purposes of showing in a museum what an emerald is without being especially beautiful.
And then I said to myself, “Someone on The Straight Dope will know this!”
Which tells me that the people selling direct to consumers online with the description “museum grade” are probably not following that guideline. If a gem is actually “of such rarity and quality that these terms are justified”, I doubt they’d be trying to unload it on eBay.
My guess is that it’s meaningless marketing fluff. I can think of a few reasons a gemstone would deserve to be in a museum:
It has some sort of historical significance (it was owned by king/queen/famous person X, or because it was found in a X-thousand year old grave, etc.)
It is of incredibly uncommon size/perfection/composition (it’s freaking huge, flawless, or is one of a handful of specimens worldwide)
It is a good representation of that particular gem (it’s just an average diamond/amethyst/whatever, in a collection designed to show people what average gems look like)
A gem in a museum for reason 1 might not be valuable in and of itself - a lot of gems we have from ancient civilizations are crappy by modern standards, but their history makes them priceless. But these wouldn’t be marketed as gems, they’d be marketed as antiquities. One in a museum for reason 3 wouldn’t be exceptionally valuable either.
To be truly “Museum Quality” for reason 2, it would have to be incredibly rare/exceptional (think about it, most of the gems you see in a museum probably have NAMES), probably not something you’d find on Ebay.
If you couldn’t tell by my user name, I really like gemstones. I see the “museum grade” label pretty often. What it means to most people is that a specimen is suitable for a nature museum archive. The seller is tying to tell buyers that the stone for sale is an acceptable example of that type of stone. The kind of thing a teacher might use as a prop for a Geology class.
Most rough stones are divided into two main types. Facet grade and non-facet grade. A facet grade emerald is a stone worth cutting and setting into a good piece of jewelry. A stone that good is expensive unless the seller just doesn’t know what they have.
Non-facet grade stones are interesting to look at but not much else. Some sellers, especially those in India for some reason, will give large lesser quality stones a quick, low detail cutting to showcase the color. They make great paperweights and conversation starters and you can get most of them for next to nothing. There are some exceptions. Rarer minerals or rare forms of common minerals can be pretty costly, but they’re still just for looking at, like you would in a museum.
Industrial diamonds are a good example of non-facet grade material. You wouldn’t put those things you see in Tiffany’s on a saw blade. A large chunk of the saw blade type stuff would still be a diamond, just not the kind you could get more than $5- $10 for.
I see the “museum grade” label pretty often. What it means to most people is that a specimen is suitable for a nature museum archive. The seller is tying to tell buyers that the stone for sale is an acceptable example of that type of stone. The kind of thing a teacher might use as a prop for a Geology class.