Assignment 11 - Carat Flashcards
The price of a gem divided by its carat weight.
Per-carat price
The international unit of measurement for gem weight (1 carat equals 0.20 gram).
Metric carat
One one-hundredth of a carat (0.01 ct.).
Point
The price per piece.
Unit price
What’s the most convenient way to weigh gems?
An electronic scale is quick, reliable, easy to use, and equally good for individual stones and large parcels.
What’s the best way to measure gems?
A millimetre gauge for individual larger gems (>3mm) or a sieve for many smaller gems (<3mm)
Which calibrated shapes and sizes are the most popular for round gemstones?
Inexpensive stones:
0.25-mm increments—from 1.50 mm or 1.75 mm through 2.00, 2.25, 2.50, 2.75, 3.00, 3.25, and 3.50 mm, then in 0.50-mm increments up to 5.00 mm, and in 1.00-mm increments after that.
Expensive stones:
0.50-mm increments, often 2.00 to 2.50 mm, 2.50 to 3.00 mm, 3.00 to 3.50 mm, and 3.50 to 4.00 mm.
Which calibrated shapes and sizes are the most popular for oval gemstones?
Commercial calibrated sizes in ovals include 4×3, 5×3, 6×4, 7×5, 8×6, 9×7, 10×8, and 12×10 mm. The 6×4-mm, 7×5-mm, and 8×6- mm sizes are the ones most widely used in prefabricated jewelry mountings.
Which calibrated shapes and sizes are the most popular?
Small calibrated squares are often channel-set in rings and bracelets, where size variations usually can’t be more than 0.10 mm one way or the other. Standard sizes in calibrated squares include 2×2, 2.5×2.5, 3×3, and 4×4 mm.
Calibrated emerald cuts can serve as alternatives to ovals in rings and pins, or as matched pairs or sets in earrings and necklaces. Standard sizes include 4×3, 5×3, 6×4, 7×5, 8×6, 9×7, and 10×8 mm.
Pear shapes can be used as matched pairs for earrings, or as single pieces for pendants. Standard sizes in pears include 5×3, 6×4, 7×5, 8×5, 9×6, and 10×7 mm.
Calibrated hearts are sometimes used as the center stones in pendants, or as alternatives to rounds or ovals as the main stones in rings or pins. Standard sizes in hearts include 4×4, 5×5, and 6×6 mm.
Calibrated marquise-shaped gems are sometimes used in small sizes as matched sets in inexpensive rings. You’ll rarely see large sizes used alone in rings or pins. Standard sizes for marquise-shaped stones include 4×2, 5×2.5, 6×3, and 8×4 mm.
Set of circular plates, each punched with precisely sized holes, used to sort small, round gems by size.
Sieve set
What are some basic tools of the gem trade?
- Tweezers
- a cleaning cloth
- scoop
- sorting pad
- matching tray
- calculator
- 10X triplet loupet
What’s the best way to present gems to your customers?
You can use clear plastic boxes with foam padding to hold individual stones, matched pairs, and sets firmly in place. Matched stones look best when they’re presented in transparent boxes.
How do gem professionals buy, sell, and keep track of gems?
Dealers must strike a delicate balance between having enough of an unusual shape on hand to satisfy one customer and minimizing the risk of being left with a shape or color that’s hard to sell if that customer suddenly stops using it.
A good way to keep the goods you purchase directly for your own inventory separate from the stones you borrow from other dealers or cutters is to give each stone or parcel of stones a different stock number. Record the number in your computer database or in your paperwork. Write it on the stone paper, too.
A small shovel made of thin metal, used for picking up gems.
Scoop
A neutrally colored paper pad on which dealers sort and show gems.
Sorting pad
