We have a long, yet complete, answer to this question about "hardness". Please see below:

Wood is a natural product and as such is prone to
everyday wear and tear. High heels, pet nails, and beater bars on a
vacuum cleaner are all the bane of wood floors. Some wood can stand up to
these demons better than others. Many consumers believe hardness is the best
shield against these issues and are ultimately disappointed when their wood
floor gets a dent, ding, or scratch.

First and foremost, the Janka test, which measures wood
hardness, is performed on a 1” thick solid piece of wood and is prone to
significant variation due to cut of wood, where it was grown, and test error.
The same red oak tree, grown in two different regions of the country, may
have wildly different Janka ratings.

Additionally, There is little to no 1” thick flooring
sold on the market. Engineered hardwood products are designed to have
significantly improved dimensional stability and can impact Janka measurements
as well.

Think of buying a wood floor like buying a diamond. there
are 5 C's in buying a diamond - Cut, Color, Clarity, Carat, and Cost. You
wouldn't buy a diamond if it had perfect color but a terrible cut and was
fractions of a carat. it's the combination of all these factors that ultimately
guide your choice. A wood floor is no different. Hardness is only
one measure of how a wood floor will perform in the home and ultimately, is one
of the worst measures. Were you to only purchase based on hardness, you
could be setting your floor up for failure. As an example, Hard Maple
(Acer Saccharum) is roughly 10% harder than oak, however, most people become
extremely satisfied with smooth maple in their homes due to the reasons we
outline below.

Use these guidelines when selecting a wood floor.
Think of it as the 5 S's of wood flooring:

Shine or Gloss - Wood is a natural product. Nothing
is more beautiful than a shiny new wood floor, however, unless you have a
relatively relaxed lifestyle, a higher gloss floor will tend to magnify life's
unexpected events over time.

Smooth or Grainy - When comparing the graininess of
different species, in general, a floor with a lot more grain and character
(such as Oak or Hickory) will tend to perform better than a floor that has
finer graining (such as Maple, Birch, or many exotics).

Scraped and Distressed Textures - The greatest thing we
ever put on wood floors was distressing and hand scraping. think of it as
pre-denting the floor in a much more fashionable way. By disrupting the
surface, it creates a floor that does a fantastic job of masking everyday wear
and tear while looking extremely elegant.

Shade - mid tone shades or colors will tend to retain
their appearance over time and stay in fashion longer than extremely light and
extremely dark colors.

Strength or Janka Hardness - This should be the final
consideration when selecting a wood floor. This is merely a relative test
and has a tremendous amount of variability depending on where the tree grows,
how quickly it was harvested, etc. If all of the other factors are
considered and let's say you are comparing a low gloss, hand scraped, honey
colored hickory and oak - then you can consider hardness as a final measure
(both low gloss, both grainy, both scraped, and both mid-toned). In that
measure the hickory floor will perform somewhat better than the oak due to its
hardness.

The hardness of Iberian is 20% softer than Northern red
oak. Keep in mind, however, that it is a low gloss, grainy, mid toned,
hand scraped floor.

I hope this was helpful! Please let us know if you have any further questions or concerns.