Know what you are buying, and why it suits you.

Laboratory-grown diamonds are diamonds created in a laboratory (by HPHT or CVD growth) rather than mined. They have essentially the same chemical, physical and optical properties as mined diamonds, and gemological labs can tell them apart with specialist instruments.

US rules require laboratory-grown diamonds to be clearly described as such, for example “laboratory-grown” or “laboratory-created”. A diamond described without a qualifier is understood to be natural. Laboratory-grown stones generally cost less than natural stones of similar size and quality; their resale market is far less established.

A grading report from a gemological lab (such as GIA or IGI) records a stone's measured characteristics: shape, measurements, carat weight, colour, clarity, and cut grade where applicable, and whether it is laboratory-grown. It does not state a value.

An appraisal is a separate document, usually prepared for insurance, that estimates a replacement value. Not every piece of jewelry comes with a grading report. If a product page doesn't say a report is included, assume it isn't, and ask us before you order.

Compare like for like: same shape, then cut, then the colour and clarity range you are comfortable with, then weight. A small step down in colour or clarity that you cannot see is often a better use of budget than a step up in carat that sacrifices cut.

Gold is alloyed with other metals for colour and strength. Yellow gold uses silver and copper; rose gold uses a higher share of copper; white gold uses whitening metals such as palladium or nickel and is usually plated with rhodium for a bright white finish. Rhodium plating wears with time and can be renewed by a jeweler.

Higher karats contain more gold and are softer, so they scratch and bend more readily. Lower karats contain more alloy. How a piece is made matters too: a solid chain and a hollow chain of the same karat wear very differently. Choose the karat for colour and budget, then look closely at construction.

Solid gold is the karat alloy throughout. Gold-plated pieces have a thin gold layer over another metal; gold-filled pieces have a thicker bonded layer; vermeil is gold over sterling silver. Karat stamps such as 10K, 14K, 18K (or 417, 585, 750) indicate karat gold.

Many coloured gemstones are treated to improve colour or clarity: heating (common in sapphire and ruby), oiling or resin filling (common in emerald), glass filling, diffusion, irradiation and coatings. US rules require disclosure of treatments that are not permanent, that need special care, or that significantly affect value. Ask whether a stone is treated and how to care for it.

A lab-created (synthetic) gemstone has the same composition as its natural counterpart but was grown in a laboratory, and must be described that way. A simulant only looks similar: cubic zirconia imitating diamond, for example. Product names should make the difference clear.

Colour matters most: look for even, saturated colour that is not too dark. Then consider clarity (emeralds typically show inclusions; many sapphires are cleaner), cut, size and setting. For rings worn daily, harder stones in protective settings last longest.

Fingers are larger at the end of the day and in warm weather. Wide bands (over about 6 mm) usually feel snugger, so consider a quarter to half size up. For the most reliable result, have the finger sized by a jeweler.

Some engagement settings sit low enough for a straight band to sit flush against them; others need a contoured or notched band. Comfort-fit bands are rounded inside and slide more easily over the knuckle than standard-fit bands.

• Cable: uniform oval links; the classic pendant chain.
• Box: square links; smooth and strong for its weight.
• Rope: twisted links that catch the light.
• Figaro: groups of short links punctuated by a longer link.
• Curb & Cuban: flattened interlocking links; bolder and heavier.
• Paperclip: long, flat elongated links; modern and light-looking.
• Wheat: woven oval links with a braided look.
• Snake & herringbone: flexible, sleek surfaces; avoid kinking.

Space layers about 2 inches apart (for example 16″, 18″ and 20″) so each one shows. Mix one textured chain with finer ones, keep one focal pendant, and stay within a metal colour family, or mix deliberately with at least two pieces of each.

Check that the pendant's bail opening is wider than the chain and its clasp, and choose a chain strong enough for the pendant's weight. Heavier pendants sit better on wider or solid chains.

Most women's bracelets are 7″ and most men's are 8″ to 8.5″. Thicker bracelets need a little more length than fine ones for the same comfort.

Start with one anchor (a watch, bangle or tennis bracelet), add a contrasting texture such as a chain, then something fine. Three to five pieces on one wrist is a comfortable range. Bracelets set with stones are best kept away from hard bangles to avoid wear.

Choose a secure box clasp with a safety catch, check the clasp regularly, and size so the bracelet cannot slip over the hand when closed.

Measure across the case, excluding the crown. As a rough guide, many people with smaller wrists favour cases around 26 to 36 mm and larger wrists 38 to 44 mm, but style matters as much as size: dress watches tend to be slimmer and smaller. The lugs should not overhang the wrist.

Ratings come from pressure tests, not real depths. Avoid hot water and saunas, and never use the crown or pushers underwater. Always follow the watch's own manual.

Open-face pocket watches show the dial at all times; hunter-case watches have a hinged cover that protects the crystal. Pair them with a chain (Albert or belt-loop style) fastened to a buttonhole, belt loop or waistcoat.

Leather bands dislike water and sweat; metal bracelets can be cleaned with a soft brush and mild soap if the case is rated for water. Lug width decides which replacement bands fit.

Necklaces, earrings and adjustable or longer bracelets are the safest choices when you don't know a size. For rings, borrow a ring they wear on the same finger and measure its inside diameter with the ring-size tool above.

Look at what they already wear: metal colour, scale (fine or bold) and whether they favour classic or modern shapes. A piece that matches what they reach for every day gets worn most.

Initials, birthstones and engraved pieces make a gift personal. Personalized pieces are made to order, so allow extra time and check the product page for its return terms.