CC/07-27Monday 27 July 2026The Auctions & Estates Desk · Auctions Desk · Los Angeles

Auctions Desk · Los AngelesAuctions & Estates · CC/07-27

Seventy carats, no reserve, on the block at Bonhams

A 70-carat diamond necklace of pear, oval and marquise stones carries a top estimate near $50,000 and no reserve when Bonhams sells more than 300 California jewels on July 28, alongside pieces by Van Cleef & Arpels, Graff and Boucheron.

By The Auctions Desk27 July 2026Brief 35 sec · Full read 2 min

PLATE IKey figures

Top California estimates · high end

70ct DIAMOND NECKLACE$50k

UNMOUNTED DIAMONDS (to)$50k

1920s 7.10ct NECKLACE$35k

Sapphire + Diamond Necklace$28k

Source On the block · Bonhams California, July 28

What changed

The arithmetic is the hook. When Bonhams sells its California Jewels auction in Los Angeles on July 28, the marquee lot is a 70-carat diamond necklace of pear, oval and marquise stones estimated at up to $50,000, and offered without reserve.

What it means · The Desk’s View

A 70-carat necklace with no reserve is a dare disguised as a lot, and someone will take it. Watch the hammer against the low estimates rather than the highs, because in a no-reserve room the honest signal is not what the trophy makes but what the ordinary lots hold.

The article3 sections · 220 words

Table I · Top California estimates · high end

	Figure
70ct DIAMOND NECKLACE	$50k
UNMOUNTED DIAMONDS (to)	$50k
1920s 7.10ct NECKLACE	$35k
Sapphire + Diamond Necklace	$28k

High estimates, USD thousands. Bonhams California Jewels, July 28. The room, not the book, sets the price. Carat Capital graphics desk. CC/2026/131

IThe dare in the catalogue

Seventy carats of graded diamond for the price of a single fine solitaire is not a market on the diamonds; it is a market on the setting, the certification and the story.

That is the estate logic of a no-reserve sale. Older mounted pieces, whose individual stones are hard to certify and expensive to break out, trade at a steep discount to the loose-goods price sheet, and a seller who wants a clean, guaranteed sale accepts it.

The estimate is a floor to walk in the door, not a valuation of the carats, and the room, not the book, sets the price.

IIEstate logic

The catalogue runs deeper than one lot.

Bonhams lists more than 300 jewels including a 1920s necklace built around a 7.10-carat diamond at a $35,000 high estimate, a necklace set with 34.95 carats of multicolored sapphires and 4.20 carats of diamonds at $28,000, and three unmounted diamonds estimated between $35,000 and $50,000, with signed pieces from Van Cleef & Arpels, Graff and Boucheron threaded through the sale.

IIIWhat the day sale measures

The venue is the point as much as the goods.

A California day sale is where the accessible middle of the jewelry market clears, the estate and secondary material that never reaches a Geneva evening, and it is a fair gauge of what ordinary collectors will pay in a summer when the metal underneath every lot has rarely been dearer.