Silver

This dilution gene, "Z", is most widely called "silver", although in Australia it may be called "taffy". Silver is the most popular term, therefore I will use it, but in some ways taffy describes the color better and with less confusion.

Silver is the gene "Z", which dilutes black, but not red, pigment.

This is like the opposite of the cream gene, which dilutes red. Silver does not dilute red pigment, but it is often mistakenly thought to do so.

The most well-known shade of silver is the Silver Dapple-- this is silver on a black base. The body is a sepia-brown color, the mane and tail are flaxen, and the body is covered in cream-colored dapples.

Silver on a bay creates a "red silver" or a "silver bay". The horse will have a red body (as red is undiluted), and a flaxen mane and chocolate-colored legs. It will look like a bay with a flaxen mane and tail-- and if you look close, you'll see the legs are not black, but a diluted sepia color.

Silver on a chestnut doesn't show up; silver can't dilute red pigment. Many horses are mistakenly called "silver chestnuts" because they have the flaxen gene, which creates a flaxen mane and legs on a chestnut/sorrel horse. This is not silver . This is only flaxen.

Silver on chestnut does not create the flaxen-maned, light-legged horse that silver on bay does.

Chocolate silver, or "chocolate flax" as it is known in the Rocky Mountain Horse breed, is the "Z" gene on a black horse, but without the dapples. The body is chocolate colored, the manes and tails flaxen, but the body is not dappled like that of a silver dapple.

Silver on seal brown or black can create a "blue silver"-- a horse that looks almost blue, but has a bluish-flaxen mane and tail.

The Rocky Mountain Horse breed is well-known for its silver horses; it also sometimes occurs in Shetlands, Australian horses and ponies, miniatures, and Icelandic Horse. It may also occur in the Quarter Horse, Paint, and at one time occured in the Freisian.

Silver is linked to an eye disorder called ASD (Anterior Segment Dysgenesis)-- but don't worry, it is only found in some silvers, and it rarely causes any type of visual trouble or blindness in the horse-- only 2 out of about 2500 silver horses examined were actually blind from ASD.

Beware that numerous other colors are called "silver" but are completely unrealted to the Silver Dapple (Z) gene. The list includes...

Gray horses, usually white grays, sometimes called 'silver'

Some buckskins are sometimes called "silver buckskin"

The sheen on Champagne horses

Smoky black horses are also called "Silver Smoky"

Lighter grullas (black duns) are sometimes called "Silver dun".

Rarely, the flaxen gene will show up on a bay horse, creating 'silver' streaks in the tail. These are called "silver" tails.

I have heard horses with the varnish effect called "silver" or "silvery"

The lighter hairs on some dun horses are called "silver" or "silvering"

"Silver" is the most usual term for the "Z" dilution, but since it is used to describe so many other unrelated things, it sometimes creates confusion. You can be sure to specify you are talking about "Z" by saying "silver dapple" in place of "silver" if you want to be clear.