While long ago many players played the guitarra with their bare fingernails today nearly all players use special fingerpicks called "unhas" made of some "plastic" material such as rigid vinyl, polypropylene, acrylic, or polycarbonate. While it is possible to buy ready made finger picks, professional players usually make their own. With a little practice you can make very good unhas. You need is a pair of scissors, a small sharp crafts knife, some sandpapers (220, 400 and 600 grit), and a sheet of 0.5 or 1.0 mm "plastic" material. Simply cut the necessary outline shape, then curve the "unha" by putting it into very hot water or over a flame and bending while hot. Then, cut away the inside of the "unha" to allow inserting your finger nail. Finally, finely shape the playing edge of the unha to your requirement with sand paper or fingernail files. The best way to affix the unha is with a 6mm by 100mm piece of surgical tape.

Plastic "tortoise shell" unhas affixed with surgical tape

The most prized material for unhas is tortoise shell which is very difficult to get as it is illegal to transport it internationally without special permits. Occasionally it is possible to find pieces of it in antique shops where it shows up as part of old cigarette cases, makeup cases, Victorian ladies handbags, tea trays, and grooming accessories. If you are not lucky enough to find any real tortoise shell, you can experiment making unhas of imitation tortoise shell from acoustic guitar pickguards. Sometimes it is difficult to acquire a material which has the appropriate qualities of rigidity and durability to make unhas. When good materials are scarce some players have been known to make unhas of old credit cards. For general use, however, I think that rigid vinyl (which you can buy from a commercial dealer of sheet plastics) is a suitable material.

Index finger and thumb unhas of rigid white vinyl (top 2 unhas), tortoise shell plastic unhas (index and thumb) made of pick guard material with surgical tape attached (bottom 2 unhas)

Commercially made unhas sold in Portugal which attach with elastic pull chords.

Above is my hand made version of a Lisboa style unha for the index finger. Notice that the playing edge (toward the bottom left in this photo) is somewhat squared as opposed to rounded as in the several photos above. In general, the playing edge of unhas for Lisboa players (both thumb and index) comes to a more or less square point whereas the unhas of Coimbra players are rounded following the profile of the natural nail.

These are molded fingerpicks made in the United States--I like these. They come in medium (M) or large (L) for the index finger and extra large for the thumb. Contact me if you want some. They are not traditional but work quite well. Since they follow the contour of the fingernail they are are more similar to the Coimbra type of unha.