There is no a universal rule widely accepted to describe the size of minerals in the collectors jargon, only conventions used by the most of collectors and dealers, with some variations each other.
In this site, we try to adhere as much as possible to this conventions, also trying to use our own set, to describe the size of minerals listed here.
This are the descriptive sizes names used in this site, hopping that all our samples showed fit into one of this definitions, and, if at a moment we need to modify this descriptions the text will be updated with the changes.
Micromounts .- Larger dimension (long, width or height) less than 2 milimeters.
Mineral samples that can only be seen at detail under optical magnification devices, like loupes or even microscopes.
Thumbnails.- Larger dimension (long, width or height) greater than 2 and less than 30 milimeters.
Mineral samples that fit in a thumb nail, that is only a description to indicate that the sample is very tiny, but not a micro.
Miniature.- Larger dimension (long, width, or height) greater than 30 and less than 60 milímeters.
Tiny samples, small, that can be the description that most people may assign to this specimens.
Small Cabinet.- Larger dimension (long, width or height) greater than 60 and less than 100 milimeters.
Specimens that fit in a small cabinet, as the name says, in the practice and day by day, we can describe this samples as "medium size", they fit very well in the hand's palm.
Cabinet.- Larger dimension (long, width or height) greater than 100 and less than 150 milimeters.
somewhat big specimens, still fit on hand''s palm but with difficult to manipulate, they fit in a "normal" size cabinet, and this is the reason which the name is only "cabinet" and not "normal cabinet".
Large Cabinet.- Larger dimension (long, width or height) greater than 150 milimeters.
Very big specimens, at least in the collectors/dealers scope, samples that need a large cabinet to be showed.
As you maybe already note, the names are descriptive only, not quantitative, they refers to the size as the people can perceive the sample, but perception varies from person to person, here lies the difficulty to define exact ranges in measurement units for each size, milimeters or inches, as stated above, they are commonly accepted conventions, but not official definitions.
In the museum collection, we will use this names to describe the size of the samples and related objects (items), we always will try to indicate samples dimensions in measurement units (milimeters/inches) however. This will help to categorize the specimens, is much easier to search/sort based on a limited set of sizes (micromount, thumbnail, cabinet, etc), than sort or search based on specific milimeter measurement variation.
If you not yet categorize your collection by size, maybe you can take advantage of this information, or even make your own set of descriptive names.
There is another size names less common or popular among collectors and dealers, such as "Toenail" or "Museum", Toenail size is larger than Thumbnail and shorter than Miniature, so we consider this redundant, and, Museum is used for very big samples, but not all huge specimens deserve the Museum word, even in their descriptive size name. so we will not use this two definitions in this site.
The following table summarize the information showed above.
|Size Name||Abbreviation||Larger Dimension||Greater than:||Less than:||Measurement unit|
|Micromount||MM||Long, Width or Height||-||2||mm|
|Thumbnail||TN||Long, Width or Height||2||30||mm|
|Miniature||Min||Long, Width or Height||30||60||mm|
|Small Cabinet||Scab||Long, Width or Height||60||100||mm|
|Cabinet||Cab||Long, Width or Height||100||150||mm|
|Large Cabinet||LCab||Long, Width or Height||150||-||mm|