This piece is simple and yet very complicated in it's power. This comes from the late 1700's and is a one of a kind piece. This is made of sterling and some kind of stone which is just some of the material.
This is called a Skin-doo,that is how you pronounce the name of this type of knife. The correct spelling is sgian-dubh.
This was taken from wikipedia below.
The sgian-dubh (/?ski??n ?du?/ skean-dhu;Scottish Gaelic pronunciation: [s?k??n?t?uh]) is a small, singled-edged knife (Gaelic sgian) worn as part of traditional Scottish Highland dress along with the kilt. Originally used for eating and preparing fruit, meat, and cutting bread and cheese - as well as serving for other more general day to day uses such as cutting material and protection, it is now worn as part of traditional Scottish dress tucked into the top of the kilt hose with only the upper portion of the hilt visible. The sgian-dubh is normally worn on the right leg, but can also be worn on the left, depending on whether the wearer is right or left-handed.
1 Etymology and spelling
6 External links
Etymology and spelling 
The name comes from the Gaelic sgian-dubh. Although the primary meaning of dubh is "black", the secondary meaning of "hidden" is at the root of sgian-dubh, based on the stories and theories surrounding the knife's origin, in particular those associated with the Highland custom of depositing weapons at the entrance to a house prior to entering as a guest. Compare also other Gaelic word-formations such as dubh-sgeir "underwater skerry" (lit. black skerry), dubh-fhacal "riddle" (lit. hidden word), dubh-cheist "enigma" (lit. hidden question).
Despite this practice, a small twin edged-dagger, (a mattucashlass, Gaelic sgian-achlais), concealed under the armpit, combined with a smaller knife, ('sgian-dubh'), concealed in the hose or boot, would offer an element of defence or of surprise if employed in attack.
As sgian is feminine, we would expect the form sgian dhubh, since a feminine noun causes initial consonant lenition in a following adjective, and indeed the every-day modern Gaelic for a normal 'black knife' is sgian dhubh. However, the term for the ceremonial knife is a set-phrase containing a fossilized historical form. In older Gaelic, a system of blocked lenition meant that lenition did not occur when the adjective started with a consonant of the same group as the final consonant of the noun, and n and d are both alveolar.
Various alternative spellings are found in English, including "skene-dhu" and "skean-dhu".
The plural is most commonly sgian-dubhs (in its various spellings) but sgians-dubh is also occasionally encountered. The proper Gaelic plural forms sg(e)inean-dubh or sgianan-dubh are only rarely encountered in English usage.
Portrait by Henry Raeburn of Alasdair Ranaldson MacDonell of Glengarry in 1812
The sgian-dubh may have evolved from the sgian-achlais, a dagger that could be concealed under the armpit. Used by the Scots of the 17th and 18th centuries, this knife was slightly larger than the average modern sgian-dubh and was carried in the upper sleeve or lining of the body of the jacket.
Courtesy and etiquette would demand that when entering the home of a friend, any concealed weapons would be revealed. It follows that the sgian-achlais would be removed from its hiding-place and displayed in the stocking top held securely by the garters.
The sgian-dubh also resembles the small skinning knife that is part of the typical set of hunting knives. These sets contain a butchering knife with a 9 to 10 inches (230 to 250 mm) blade, and a skinner with a blade of about 4 inches (100 mm). These knives usually had antler handles, as do many early sgian-dubhs. The larger knife is likely the ancestor of the modern dirk.
The bog oak, jet black in appearance, was a very hard wood suitable for the purpose. The handles on the stag knives simulate horn which was also traditionally used. Any ornamentation is merely a reflection of the Highlander's lack of confidence in paper money which resulted in him embellishing much of his personal wearing apparel with silver and cairngorm stones which are of value. Thus he carried on his person most of his worldly wealth. The black dagger (sgian-dubh) was usually carried in a place of concealment very often under his armpit (or oxter). This gives support to the view that 'black' does not refer only to the colour of the handle but implies 'covert' - as in (as stated previously) blackmail or black market. When the Highlander visited a house on his travels having deposited all his other weapons at the front door he did not divest himself of his concealed dagger, since in these far off days it was unsafe to be ever totally unarmed, not because he feared his host but rather because he feared intrusions from outside. Accordingly although retaining the dagger; out of courtesy to his host he removed it from its place of concealment and put it somewhere where his host could see it, invariably in his stocking on the side of his hand (right or left-handed).
The sgian-dubh can be seen in portraits of kilted men of the mid-19th century. A portrait by Sir Henry Raeburn of Colonel Alasdair Ranaldson MacDonell of Glengarry hangs in the National Gallery of Scotland; it shows hanging from his belt on his right hand side a Highland Scottish dirk, and visible at the top of his right stocking what appears to be a nested set of two sgian-dubhs. A similar sgian-dubh is in the collection of The National Museum of Antiquities of Scotland.
THIS PARTICULAR KNIFE COMES FROM EDINBURGH SCOTLAND. THIS WAS A RITUAL KNIFE AND YOU KNOW THIS BECAUSE OF THE CUT OUT ON THE KNIFE FOR THE BLOOD TO FLOW. THIS PARTICULAR MAGICIAN AND ASSASSIN THAT OWN THIS WAS VERY POWERFUL AND IT WAS CARRIED IN THE KNIFE. WITH THIS YOU CAN DO AND CALL UP ANYTHING. YOU HAVE THE ABILITY TO REDO YOUR LIFE AS SOMEONE ELSE,CALL THINGS INTO BEING,MAKE THINGS HAPPEN OR STOP THEM,CAUSE WEATHER CHANGES. CREATE A CIRCLE OF MAGIC AND CONJURATION. BAPTISE YOURSELF INTO ANOTHER REALM OR GIVE YOURSELF FULL POWER OF ANY TYPE OF MAGIC. THIS LIST GOES ON. THIS IS ONE OF A KIND AND COMES WITH A FIRE DRAGON.